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.
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…
</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>
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.
</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>
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.
</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>
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.
</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.
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…
</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;">
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.
</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;">
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.
</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;">
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.
</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.
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 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)
{
}
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 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.
