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Posts Tagged ‘.Net’

.Net, Silverlight → WP7 – Context Menu From Listbox

August 26th, 2010 by Ryan Alford

In writing one of my Windows Phone 7 applications, I needed to do a allow the user to delete an entry from a ListBox. Since my ListBox didn’t have enough room for an actual delete button, I decided I would use a ContextMenu to do it. To my surprise, even though the OS seems to support a long press action(the way to uninstall an application), that action doesn’t seem to be available to developers(or not that I could find). So I decided to roll my own using the [b]MouseLeftButtonDown [/b]and [b]MouseLeftButtonUp [/b]events, and a [b]DispatcherTimer[/b]. Add these two using statements to the top of the code…

 using System.Collections.ObjectModel; using System.Windows.Threading;

So first, we need our initial code to get the [b]ListBox [/b]populated. I created a [b]Person [/b]class just for simplistic reasons.

 public class Person {     public string FirstName { get; set; }     public string LastName { get; set; } }

Next, I will set up the [b]ListBox [/b]to simply show the [b]FirstName [/b]of the [b]Person[/b].

 <ListBox      Name="lbNames"      Height="240"      HorizontalAlignment="Left"      Margin="10,119,0,0"      VerticalAlignment="Top"      Width="460"     ItemsSource="{Binding}">                      <ListBox.ItemTemplate>         <DataTemplate>             <StackPanel>                 <TextBlock Text="{Binding FirstName}" />             </StackPanel>         </DataTemplate>     </ListBox.ItemTemplate>                  </ListBox>

Now I will create an generic [b]ObservableCollection [/b]object to store the [b]Person [/b]objects. This will be a class level variable since it will be accessed from multiple events.

 public partial class MainPage : PhoneApplicationPage {     ObservableCollection<Person> personList = new ObservableCollection<Person>();      // Constructor     public MainPage()     {         InitializeComponent();          this.Loaded += new RoutedEventHandler(MainPage_Loaded);     }      void MainPage_Loaded(object sender, RoutedEventArgs e)     {         personList.Add(new Person() { FirstName = "John", LastName = "Doe" });         personList.Add(new Person() { FirstName = "Jane", LastName = "Doe" });         personList.Add(new Person() { FirstName = "John", LastName = "Adams" });          lbNames.ItemsSource = personList;     } }

Now I need to create the event handlers for the [b]MouseLeftButtonDown [/b]and [b]MouseLeftButtonUp [/b]events. This can simply be done by using the [b]Events [/b]list from the [b]Properties [/b]window in the designer.

 private void lbNames_MouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e) {  }  private void lbNames_MouseLeftButtonUp(object sender, System.Windows.Input.MouseButtonEventArgs e) {  }

We now need to create two class level objects: a [b]DispatcherTimer [/b]object, and a [b]Person [/b]object. These are class level because they will need to be accessed from different events. We will also subscribe to the Tick event for the timer.

 ObservableCollection<Person> personList = new ObservableCollection<Person>();  DispatcherTimer timer;  Person selectedPerson = null;  // Constructor public MainPage() {     InitializeComponent();      this.Loaded += new RoutedEventHandler(MainPage_Loaded);      timer = new DispatcherTimer();     timer.Tick += delegate(object s, EventArgs e)     {      }; }

Next, we will add a [b]Popup [/b]in XAML. This can go above or below the [b]ListBox[/b] that is currently holding the names.

 <Popup      x:Name="DeleteContextMenu"      Height="200"      Width="400">      <!-- This is a ListBox as an ItemTemplate for the Popup -->     <ListBox          x:Name="lbDeleteContextMenu"         Background="White"         SelectionChanged="DeleteContextMenu_SelectionChanged">          <ListBoxItem             Content="Delete Person"              Foreground="Red"             FontSize="25"             FontWeight="Bold"/>      </ListBox>  </Popup>

And the event handler for selecting the Delete item…

 private void DeleteContextMenu_SelectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e) {  }

Here is how it’s going to work. When the user presses down, we will start the timer. When the user releases, then we stop the timer. So if the timer’s interval is reached, we know that the user was holding down on the screen, so we will display the popup. So now we move to our code. First we are going to handle the [b]MouseLeftButtonDown [/b]event.

 private void lbNames_MouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e) {     // if there is no person selected, then there is no person to delete     //   no need to do any code if nothing is selected     if (selectedPerson == null)         return;      // gets the position of the mouse cursor to set the Margin     //    of the Popup to show at the mouse coordinates.  You     //    may need to tweak these values to get it to display in     //    the correct location.     Point position = e.GetPosition((UIElement)this);     DeleteContextMenu.Margin = new Thickness(position.X, position.Y - 200, 20, 0);      // sets the interval to 1.1 seconds.  This means the user will need      //    to hold down on the screen for 1.1 seconds before we determine     //    to show the ContextMenu.     timer.Interval = TimeSpan.FromMilliseconds(1100);     timer.Start(); }

Next, we will do our code for the [b]MouseLeftButtonUp[/b] event

 private void lbNames_MouseLeftButtonUp(object sender, System.Windows.Input.MouseButtonEventArgs e) {     // stop the timer when the user releases the screen     timer.Stop();      // sets the class level variable to the selected row     selectedPerson = lbNames.SelectedItem as Person; }

Now for our code in the [b]Tick [/b]event for the [b]Timer[/b].

 // Constructor public MainPage() {     InitializeComponent();      this.Loaded += new RoutedEventHandler(MainPage_Loaded);      timer = new DispatcherTimer();     timer.Tick += delegate(object s, EventArgs e)     {         // stop the timer so that it doesn't popup the Context menu again         timer.Stop();          // since we are using the same ListBox over and over, this will         //   make it so when the Context Menu is shown, there will be no         //   selected item from any previous showing of the Context Menu         lbDeleteContextMenu.SelectedIndex = -1;          // opens the Context Menu         DeleteContextMenu.IsOpen = true;     }; }

Last, we have our code from the [b]SelectionChanged [/b]event for the [b]ListBox [/b]that is part of the Context Menu.

 private void DeleteContextMenu_SelectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e) {     // in the Timer's Tick event, we set the SelectedIndex of the     //   Context Menu's Listbox back to -1.  However, this does     //   fire the SelectionChanged event.  This code will handle that.     if (lbDeleteContextMenu.SelectedIndex == -1)         return;      // closes the Context Menu     DeleteContextMenu.IsOpen = false;      if (selectedPerson == null)         return;      // removes the selected person from the list     personList.Remove(selectedPerson);      // since we are using an ObservableCollection, we do not have     //   to rebind the list to the ListBox.      selectedPerson = null; }

Now you can run the application, and you will see the list show up. You must click on an item first before clicking and holding to show the Context Menu.

So I decided to roll my own using the [b]MouseLeftButtonDown [/b]and [b]MouseLeftButtonUp [/b]events, and a [b]DispatcherTimer[/b].

Add these two using statements to the top of the code…

</pre>
</div>
<div>using System.Collections.ObjectModel;</div>
<div>using System.Windows.Threading;</div>
<div>

So first, we need our initial code to get the [b]ListBox [/b]populated. I created a [b]Person [/b]class just for simplistic reasons.

</pre>
</div>
<div>public class Person</div>
<div>{</div>
<div>public string FirstName { get; set; }</div>
<div>public string LastName { get; set; }</div>
<div>}</div>
<div>

Next, I will set up the [b]ListBox [/b]to simply show the [b]FirstName [/b]of the [b]Person[/b].

</pre>
</div>
<div><ListBox</div>
<div>Name="lbNames"</div>
<div>Height="240"</div>
<div>HorizontalAlignment="Left"</div>
<div>Margin="10,119,0,0"</div>
<div>VerticalAlignment="Top"</div>
<div>Width="460"</div>
<div>ItemsSource="{Binding}"></div>
<div><ListBox.ItemTemplate></div>
<div><DataTemplate></div>
<div><StackPanel></div>
<div><TextBlock Text="{Binding FirstName}" /></div>
<div></StackPanel></div>
<div></DataTemplate></div>
<div></ListBox.ItemTemplate></div>
<div></ListBox></div>
<div>

Now I will create an generic [b]ObservableCollection [/b]object to store the [b]Person [/b]objects. This will be a class level variable since it will be accessed from multiple events.

</pre>
</div>
<div>public partial class MainPage : PhoneApplicationPage</div>
<div>{</div>
<div>ObservableCollection<Person> personList = new ObservableCollection<Person>();</div>
<div>// Constructor</div>
<div>public MainPage()</div>
<div>{</div>
<div>InitializeComponent();</div>
<div>this.Loaded += new RoutedEventHandler(MainPage_Loaded);</div>
<div>}</div>
<div>void MainPage_Loaded(object sender, RoutedEventArgs e)</div>
<div>{</div>
<div>personList.Add(new Person() { FirstName = "John", LastName = "Doe" });</div>
<div>personList.Add(new Person() { FirstName = "Jane", LastName = "Doe" });</div>
<div>personList.Add(new Person() { FirstName = "John", LastName = "Adams" });</div>
<div>lbNames.ItemsSource = personList;</div>
<div>}</div>
<div>}</div>
<div>

</pre>
</div>
<div>private void lbNames_MouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e)</div>
<div>{</div>
<div>}</div>
<div>private void lbNames_MouseLeftButtonUp(object sender, System.Windows.Input.MouseButtonEventArgs e)</div>
<div>{</div>
<div>}</div>
<div>

</pre>
</div>
<div>ObservableCollection<Person> personList = new ObservableCollection<Person>();</div>
<div>DispatcherTimer timer;</div>
<div>Person selectedPerson = null;</div>
<div>// Constructor</div>
<div>public MainPage()</div>
<div>{</div>
<div>InitializeComponent();</div>
<div>this.Loaded += new RoutedEventHandler(MainPage_Loaded);</div>
<div>timer = new DispatcherTimer();</div>
<div>timer.Tick += delegate(object s, EventArgs e)</div>
<div>{</div>
<div>};</div>
<div>}</div>
<div>

Next, we will add a [b]Popup [/b]in XAML. This can go above or below the [b]ListBox[/b] that is currently holding the names.

</pre>
</div>
<div><Popup</div>
<div>x:Name="DeleteContextMenu"</div>
<div>Height="200"</div>
<div>Width="400"></div>
<div><!-- This is a ListBox as an ItemTemplate for the Popup --></div>
<div><ListBox</div>
<div>x:Name="lbDeleteContextMenu"</div>
<div>Background="White"</div>
<div>SelectionChanged="DeleteContextMenu_SelectionChanged"></div>
<div><ListBoxItem</div>
<div>Content="Delete Person"</div>
<div>Foreground="Red"</div>
<div>FontSize="25"</div>
<div>FontWeight="Bold"/></div>
<div></ListBox></div>
<div></Popup></div>
<div>

And the event handler for selecting the Delete item…

</pre>
</div>
<div>private void DeleteContextMenu_SelectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e)</div>
<div>{</div>
<div>}</div>
<div>

So now we move to our code. First we are going to handle the [b]MouseLeftButtonDown [/b]event.

</pre>
</div>
<div>private void lbNames_MouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e)</div>
<div>{</div>
<div>// if there is no person selected, then there is no person to delete</div>
<div>//   no need to do any code if nothing is selected</div>
<div>if (selectedPerson == null)</div>
<div>return;</div>
<div>// gets the position of the mouse cursor to set the Margin</div>
<div>//    of the Popup to show at the mouse coordinates.  You</div>
<div>//    may need to tweak these values to get it to display in</div>
<div>//    the correct location.</div>
<div>Point position = e.GetPosition((UIElement)this);</div>
<div>DeleteContextMenu.Margin = new Thickness(position.X, position.Y - 200, 20, 0);</div>
<div>// sets the interval to 1.1 seconds.  This means the user will need</div>
<div>//    to hold down on the screen for 1.1 seconds before we determine</div>
<div>//    to show the ContextMenu.</div>
<div>timer.Interval = TimeSpan.FromMilliseconds(1100);</div>
<div>timer.Start();</div>
<div>}</div>
<div>

Next, we will do our code for the [b]MouseLeftButtonUp[/b] event

</pre>
</div>
<div>private void lbNames_MouseLeftButtonUp(object sender, System.Windows.Input.MouseButtonEventArgs e)</div>
<div>{</div>
<div>// stop the timer when the user releases the screen</div>
<div>timer.Stop();</div>
<div>// sets the class level variable to the selected row</div>
<div>selectedPerson = lbNames.SelectedItem as Person;</div>
<div>}</div>
<div>

Now for our code in the [b]Tick [/b]event for the [b]Timer[/b].

</pre>
</div>
<div>// Constructor</div>
<div>public MainPage()</div>
<div>{</div>
<div>InitializeComponent();</div>
<div>this.Loaded += new RoutedEventHandler(MainPage_Loaded);</div>
<div>timer = new DispatcherTimer();</div>
<div>timer.Tick += delegate(object s, EventArgs e)</div>
<div>{</div>
<div>// stop the timer so that it doesn't popup the Context menu again</div>
<div>timer.Stop();</div>
<div>// since we are using the same ListBox over and over, this will</div>
<div>//   make it so when the Context Menu is shown, there will be no</div>
<div>//   selected item from any previous showing of the Context Menu</div>
<div>lbDeleteContextMenu.SelectedIndex = -1;</div>
<div>// opens the Context Menu</div>
<div>DeleteContextMenu.IsOpen = true;</div>
<div>};</div>
<div>}</div>
<div>

Last, we have our code from the [b]SelectionChanged [/b]event for the [b]ListBox [/b]that is part of the Context Menu.

</pre>
</div>
<div>private void DeleteContextMenu_SelectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e)</div>
<div>{</div>
<div>// in the Timer's Tick event, we set the SelectedIndex of the</div>
<div>//   Context Menu's Listbox back to -1.  However, this does</div>
<div>//   fire the SelectionChanged event.  This code will handle that.</div>
<div>if (lbDeleteContextMenu.SelectedIndex == -1)</div>
<div>return;</div>
<div>// closes the Context Menu</div>
<div>DeleteContextMenu.IsOpen = false;</div>
<div>if (selectedPerson == null)</div>
<div>return;</div>
<div>// removes the selected person from the list</div>
<div>personList.Remove(selectedPerson);</div>
<div>// since we are using an ObservableCollection, we do not have</div>
<div>//   to rebind the list to the ListBox.</div>
<div>selectedPerson = null;</div>
<div>}</div>
<div>

Now you can run the application, and you will see the list show up. You must click on an item first before clicking and holding to show the Context Menu.

So I decided to roll my own using the [b]MouseLeftButtonDown [/b]and [b]MouseLeftButtonUp [/b]events, and a [b]DispatcherTimer[/b].

Add these two using statements to the top of the code…

</pre>
</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">using System.Collections.ObjectModel;</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">using System.Windows.Threading;</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">

So first, we need our initial code to get the [b]ListBox [/b]populated. I created a [b]Person [/b]class just for simplistic reasons.

</pre>
</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">public class Person</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">{</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">public string FirstName { get; set; }</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">public string LastName { get; set; }</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">}</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">

Next, I will set up the [b]ListBox [/b]to simply show the [b]FirstName [/b]of the [b]Person[/b].

</pre>
</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;"><ListBox</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">Name="lbNames"</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">Height="240"</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">HorizontalAlignment="Left"</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">Margin="10,119,0,0"</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">VerticalAlignment="Top"</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">Width="460"</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">ItemsSource="{Binding}"></div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;"><ListBox.ItemTemplate></div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;"><DataTemplate></div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;"><StackPanel></div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;"><TextBlock Text="{Binding FirstName}" /></div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;"></StackPanel></div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;"></DataTemplate></div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;"></ListBox.ItemTemplate></div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;"></ListBox></div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">

Now I will create an generic [b]ObservableCollection [/b]object to store the [b]Person [/b]objects. This will be a class level variable since it will be accessed from multiple events.

</pre>
</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">public partial class MainPage : PhoneApplicationPage</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">{</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">ObservableCollection<Person> personList = new ObservableCollection<Person>();</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">// Constructor</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">public MainPage()</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">{</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">InitializeComponent();</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">this.Loaded += new RoutedEventHandler(MainPage_Loaded);</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">}</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">void MainPage_Loaded(object sender, RoutedEventArgs e)</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">{</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">personList.Add(new Person() { FirstName = "John", LastName = "Doe" });</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">personList.Add(new Person() { FirstName = "Jane", LastName = "Doe" });</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">personList.Add(new Person() { FirstName = "John", LastName = "Adams" });</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">lbNames.ItemsSource = personList;</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">}</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">}</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">

</pre>
</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">private void lbNames_MouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e)</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">{</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">}</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">private void lbNames_MouseLeftButtonUp(object sender, System.Windows.Input.MouseButtonEventArgs e)</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">{</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">}</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">

</pre>
</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">ObservableCollection<Person> personList = new ObservableCollection<Person>();</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">DispatcherTimer timer;</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">Person selectedPerson = null;</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">// Constructor</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">public MainPage()</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">{</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">InitializeComponent();</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">this.Loaded += new RoutedEventHandler(MainPage_Loaded);</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">timer = new DispatcherTimer();</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">timer.Tick += delegate(object s, EventArgs e)</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">{</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">};</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">}</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">

Next, we will add a [b]Popup [/b]in XAML. This can go above or below the [b]ListBox[/b] that is currently holding the names.

</pre>
</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;"><Popup</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">x:Name="DeleteContextMenu"</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">Height="200"</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">Width="400"></div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;"><!-- This is a ListBox as an ItemTemplate for the Popup --></div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;"><ListBox</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">x:Name="lbDeleteContextMenu"</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">Background="White"</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">SelectionChanged="DeleteContextMenu_SelectionChanged"></div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;"><ListBoxItem</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">Content="Delete Person"</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">Foreground="Red"</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">FontSize="25"</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">FontWeight="Bold"/></div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;"></ListBox></div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;"></Popup></div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">

And the event handler for selecting the Delete item…

</pre>
</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">private void DeleteContextMenu_SelectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e)</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">{</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">}</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">

So now we move to our code. First we are going to handle the [b]MouseLeftButtonDown [/b]event.

</pre>
</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">private void lbNames_MouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e)</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">{</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">// if there is no person selected, then there is no person to delete</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">//   no need to do any code if nothing is selected</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">if (selectedPerson == null)</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">return;</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">// gets the position of the mouse cursor to set the Margin</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">//    of the Popup to show at the mouse coordinates.  You</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">//    may need to tweak these values to get it to display in</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">//    the correct location.</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">Point position = e.GetPosition((UIElement)this);</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">DeleteContextMenu.Margin = new Thickness(position.X, position.Y - 200, 20, 0);</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">// sets the interval to 1.1 seconds.  This means the user will need</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">//    to hold down on the screen for 1.1 seconds before we determine</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">//    to show the ContextMenu.</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">timer.Interval = TimeSpan.FromMilliseconds(1100);</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">timer.Start();</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">}</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">

Next, we will do our code for the [b]MouseLeftButtonUp[/b] event

</pre>
</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">private void lbNames_MouseLeftButtonUp(object sender, System.Windows.Input.MouseButtonEventArgs e)</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">{</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">// stop the timer when the user releases the screen</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">timer.Stop();</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">// sets the class level variable to the selected row</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">selectedPerson = lbNames.SelectedItem as Person;</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">}</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">

Now for our code in the [b]Tick [/b]event for the [b]Timer[/b].

</pre>
</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">// Constructor</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">public MainPage()</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">{</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">InitializeComponent();</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">this.Loaded += new RoutedEventHandler(MainPage_Loaded);</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">timer = new DispatcherTimer();</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">timer.Tick += delegate(object s, EventArgs e)</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">{</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">// stop the timer so that it doesn't popup the Context menu again</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">timer.Stop();</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">// since we are using the same ListBox over and over, this will</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">//   make it so when the Context Menu is shown, there will be no</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">//   selected item from any previous showing of the Context Menu</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">lbDeleteContextMenu.SelectedIndex = -1;</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">// opens the Context Menu</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">DeleteContextMenu.IsOpen = true;</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">};</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">}</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">

Last, we have our code from the [b]SelectionChanged [/b]event for the [b]ListBox [/b]that is part of the Context Menu.

</pre>
</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">private void DeleteContextMenu_SelectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e)</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">{</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">// in the Timer's Tick event, we set the SelectedIndex of the</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">//   Context Menu's Listbox back to -1.  However, this does</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">//   fire the SelectionChanged event.  This code will handle that.</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">if (lbDeleteContextMenu.SelectedIndex == -1)</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">return;</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">// closes the Context Menu</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">DeleteContextMenu.IsOpen = false;</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">if (selectedPerson == null)</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">return;</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">// removes the selected person from the list</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">personList.Remove(selectedPerson);</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">// since we are using an ObservableCollection, we do not have</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">//   to rebind the list to the ListBox.</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">selectedPerson = null;</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">}</div>
<div id="_mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;">

Now you can run the application, and you will see the list show up. You must click on an item first before clicking and holding to show the Context Menu.

To my surprise, even though the OS seems to support a long press action(the way to uninstall an application), that action doesn’t seem to be available to developers(or not that I could find).

So I decided to roll my own using the MouseLeftButtonDown and MouseLeftButtonUp events, and a DispatcherTimer.

Add these two using statements to the top of the code…

using System.Collections.ObjectModel;
using System.Windows.Threading;

So first, we need our initial code to get the ListBox populated. I created a Person class just for simplistic reasons.

public class Person
{
     public string FirstName { get; set; }
     public string LastName { get; set; }
}

Next, I will set up the ListBox to simply show the FirstName of the Person.

<ListBox
     Name="lbNames"
     Height="240"
     HorizontalAlignment="Left"
     Margin="10,119,0,0"
     VerticalAlignment="Top"
     Width="460"
     ItemsSource="{Binding}">

     <ListBox.ItemTemplate>
          <DataTemplate>
               <StackPanel>
                    <TextBlock Text="{Binding FirstName}" />
               </StackPanel>
          </DataTemplate>
     </ListBox.ItemTemplate>
</ListBox>

Now I will create an generic ObservableCollection object to store the Person objects. This will be a class level variable since it will be accessed from multiple events.

public partial class MainPage : PhoneApplicationPage
{
    ObservableCollection<Person> personList = new ObservableCollection<Person>();

    // Constructor
    public MainPage()
    {
        InitializeComponent();

        this.Loaded += new RoutedEventHandler(MainPage_Loaded);
    }

    void MainPage_Loaded(object sender, RoutedEventArgs e)
    {
        personList.Add(new Person() { FirstName = "John", LastName = "Doe" });
        personList.Add(new Person() { FirstName = "Jane", LastName = "Doe" });
        personList.Add(new Person() { FirstName = "John", LastName = "Adams" });

        lbNames.ItemsSource = personList;
    }
}

Now I need to create the event handlers for the MouseLeftButtonDown and MouseLeftButtonUp events. This can simply be done by using the Events list from the Properties window in the designer.

private void lbNames_MouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e)
{

}

private void lbNames_MouseLeftButtonUp(object sender, System.Windows.Input.MouseButtonEventArgs e)
{

}

We now need to create two class level objects: a DispatcherTimer object, and a Person object. These are class level because they will need to be accessed from different events. We will also subscribe to the Tick event for the timer.

ObservableCollection<Person> personList = new ObservableCollection<Person>();

DispatcherTimer timer;

Person selectedPerson = null;

// Constructor
public MainPage()
{
    InitializeComponent();

    this.Loaded += new RoutedEventHandler(MainPage_Loaded);

    timer = new DispatcherTimer();
    timer.Tick += delegate(object s, EventArgs e)
    {

    };
}

Next, we will add a Popup in XAML. This can go above or below the ListBox that is currently holding the names.

<Popup
    x:Name="DeleteContextMenu"
    Height="200"
    Width="400">

    <!-- This is a ListBox as an ItemTemplate for the Popup -->
    <ListBox
        x:Name="lbDeleteContextMenu"
        Background="White"
        Selectionchanged="DeleteContextMenu_Selectionchanged">

        <ListBoxItem
            Content="Delete Person"
            Foreground="Red"
            FontSize="25"
            FontWeight="Bold"/>

    </ListBox>

</Popup>

And the event handler for selecting the Delete item…

private void DeleteContextMenu_Selectionchanged(object sender, System.Windows.Controls.SelectionchangedEventArgs e)
{

}

So now we move to our code. First we are going to handle the MouseLeftButtonDown event.

private void lbNames_MouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e)
{
    // if there is no person selected, then there is no person to delete
    //   no need to do any code if nothing is selected
    if (selectedPerson == null)
        return;

    // gets the position of the mouse cursor to set the Margin
    //    of the Popup to show at the mouse coordinates.  You
    //    may need to tweak these values to get it to display in
    //    the correct location.
    Point position = e.GetPosition((UIElement)this);
    DeleteContextMenu.Margin = new Thickness(position.X, position.Y - 200, 20, 0);

    // sets the interval to 1.1 seconds.  This means the user will need
    //    to hold down on the screen for 1.1 seconds before we determine
    //    to show the ContextMenu.
    timer.Interval = TimeSpan.FromMilliseconds(1100);
    timer.Start();
}

Next, we will do our code for the MouseLeftButtonUp event

private void lbNames_MouseLeftButtonUp(object sender, System.Windows.Input.MouseButtonEventArgs e)
{
    // stop the timer when the user releases the screen
    timer.Stop();

    // sets the class level variable to the selected row
    selectedPerson = lbNames.SelectedItem as Person;
}

Now for our code in the Tick event for the Timer.

// Constructor
public MainPage()
{
    InitializeComponent();

    this.Loaded += new RoutedEventHandler(MainPage_Loaded);

    timer = new DispatcherTimer();
    timer.Tick += delegate(object s, EventArgs e)
    {
        // stop the timer so that it doesn't popup the Context menu again
        timer.Stop();

        // since we are using the same ListBox over and over, this will
        //   make it so when the Context Menu is shown, there will be no
        //   selected item from any previous showing of the Context Menu
        lbDeleteContextMenu.SelectedIndex = -1;

        // opens the Context Menu
        DeleteContextMenu.IsOpen = true;
    };
}

Last, we have our code from the SelectionChanged event for the ListBox that is part of the Context Menu.

private void DeleteContextMenu_Selectionchanged(object sender, System.Windows.Controls.SelectionchangedEventArgs e)
{
    // in the Timer's Tick event, we set the SelectedIndex of the
    //   Context Menu's Listbox back to -1.  However, this does
    //   fire the Selectionchanged event.  This code will handle that.
    if (lbDeleteContextMenu.SelectedIndex == -1)
        return;

    // closes the Context Menu
    DeleteContextMenu.IsOpen = false;

    if (selectedPerson == null)
        return;

    // removes the selected person from the list
    personList.Remove(selectedPerson);

    // since we are using an ObservableCollection, we do not have
    //   to rebind the list to the ListBox.

    selectedPerson = null;
}

Now you can run the application, and you will see the list show up. You must click on an item first before clicking and holding to show the Context Menu.

Tags: .Net, C#, Silverlight, WP7, wp7dev

.Net → C# – Twitter API For Desktop

10 Comments

December 17th, 2009 by Ryan Alford

I made a post almost 3 months ago about a .Net Twitter API that I had done. Since then, I have made some modifications to the API. I have added a couple of more features. I also included various classes from the System.Web namespace so that I wouldn’t need a reference to that namespace. This allows the API to be used on a mobile device with a very small footprint(the System.Web.dll file is 5MB in size, my .dll is 52KB).

I am missing a few features from my API. Most notably the new “Retweet” functionality and the “Lists” functionality. I am also missing some of the account methods. Other than that, I believe I have most, if not all, of the other methods.

This API supports both Basic Auth and OAuth. I would advise to use OAuth, since Twitter will be depreciating Basic Auth in June 2010. To learn more about how OAuth works, check out my other blog post where I try to explain OAuth.

Remember that this API is for the Desktop OAuth only. Feel free to download it and make changes to allow OAuth from a web application(yes, they are different “workflows”). Basic Auth should work for both Desktop and Web applications.

I give credit to Shannon Whitley for his original OAuth code. I made some modifications to it, but the base code of the OAuth is his.

Here is a code snippet on using the API for OAuth authorization.

// creats instance and sets Consumer and ConsumerSecret values
TwitEclipseAPI twit = new TwitEclipseAPI();
twit.OAuthConsumerKey = "yourConsumerKey";
twit.OAuthConsumerSecret = "yourConsumerSecret";

// makes request to get unauthorized request token
// The method will concatenate the request token to Twitter's Desktop OAuth
//    url (http://twitter.com/oauth/authorize)
string url = twit.OAuthGetUnauthorizedRequestToken();

// opens the user's default browser and browses to Twitter's OAuth page
Process.Start(url);

//  You will need to get the PIN from the user
//  I just created a popup and have the user enter the PIN
//       into a textbox in the popup
frmPinPopup popup = new frmPinPopup();
popup.ShowDialog();

string PIN = popup.PIN;
popup.Dispose();

// Gets the Token and TokenSecret that will be needed for all
//   subsequent requests.  You will need to save these values to keep
//   from forcing the user to authorize your application everytime they
//   open your application.
twit.OAuthRequestAccessToken(PIN);

// You can check for success by checking the OAuthAccessToken
//    and OAuthAccessTokenSecret values.  If they are populated, then
//    it was successful.  If they are empty, then it failed.
if (!string.IsNullOrEmpty(twit.OAuthAccessToken) && !string.IsNullOrEmpty(twit.OAuthAccessTokenSecret))
{
    MessageBox.Show("Authorization Successful");
}

Each method of the API will check the OAuthAccessToken and OAuthAccessTokenSecret values to determine whether it needs to do the request using OAuth or Basic Auth.

I have put the code on CodePlex. It will contain both the .dll file, and the source code. I felt it was easier to keep up with using CodePlex.

If you have code questions, you can post here. However, if you are on Google Wave, you can go here. If you would like Google Wave, I have about 20 invitations that I can send out. Using Google Wave would be much better since we could exchange code using a code snippet tool.

Tags: .Net, C#, Desktop, OAuth, Twitter

.Net → TwitEclipse – My Twitter Desktop Client

3 Comments

October 12th, 2009 by Ryan Alford

I have released a BETA version of my Twitter Desktop Client called TwitEclipse. I have been writing a Twitter API library in .Net for a while now, and figured I might as well write a desktop client also.

The client uses .Net 3.5 SP1 and WPF. It was a great learning experience to learn WPF since I had almost no previous experience with it.

If you want to download it and test it out, you can download it from here. Remember that it is a BETA. You could run into issues. If you do, be sure to let me know so I can fix them. I will also be adding additional features to the app once I get a chance.

I will be releasing my Twitter API library soon also.

Tags: .Net, C#, OAuth, Twitter, twitter desktop client, wpf

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