- Investigating Unsupported Controls in the .NET Compact Framework
- Investigating Unsupported System.Windows.Forms Functionality in the .NET Compact Framework
- Working with the Visual Studio .NET Form Designer
- Understanding the Different Windows Forms Target Platforms
- Working with the Form Control
- Programming the Button Control
- Using the TextBox Control
- Using the Label Control
- Working with RadioButton Controls
- Using the CheckBox Control
- Using the ComboBox Control
- Using the ListBox Control
- Using the NumericUpDown Control
- Using the DomainUpDown Control
- Programming the ProgressBar Control
- Using the StatusBar Control
- Using the TrackBar Control
- Using the ToolBar Control
- Adding Menus with the MainMenu Control
- Using a ContextMenu Control in an Application
- Using the Timer Control
- Using the OpenFileDialog and SaveFileDialog Controls
- Using the Panel Control
- Using the HScrollBar and VScrollBar Controls
- Using the ImageList Control
- Using the PictureBox Control
- Using the ListView Control
- Using the TabControl Control
- Using the TreeView Control
- Working with the DataGrid Control
- In Brief
This chapter is from the book
This chapter is from the book
This chapter is from the book
Using a ContextMenu Control in an Application
The ContextMenu control is almost exactly like the MainMenu control except that the context menus are associated with other controls, whereas the MainMenu is associated with the application's form. ContextMenus are also known as pop-up menus that appear when you tap-and-hold a control on Pocket PC or right-click a control on Windows CE. Tap-and-hold can be simulated on the Pocket PC emulator by pressing and holding the left mouse button.
To add a ContextMenu to an application, drag the control from the ToolBox onto the application. The new ContextMenu control will appear in the panel at the bottom of the Form Designer. When the ContextMenu is selected, the Form Designer paints the control in the same place as the MainMenu control. This is done only for design purposes. At runtime the ContextMenu will appear above its respective control. To add MenuItem to the ContextMenu, click the ContextMenu on the Form or click the Edit Menu link in the Properties window. The Edit Menu link is visible only when the ContextMenu is selected.
You can also create ContextMenu controls at runtime. First, a ContextMenu control must be instantiated. Next add MenuItem objects to it, and then set the ContextMenu property of a control to the ContextMenu instance. The following code demonstrates how to add a ContextMenu at runtime:
C# ContextMenu cMenu = new ContextMenu(); MenuItem menuItem1 = new MenuItem(); MenuItem menuItem2 = new MenuItem(); menuItem1.Text = "Default Item 1"; menuItem2.Text = "Default Item 2"; // Add menuItem2 as a child of menuItem1 menuItem1.MenuItems.Add(this.menuItem2); // Add menuItem1 to the context menu cMenu.MenuItems.Add(this.menuItem1); // Add the context menu to a label control label1.ContextMenu = cMenu; VB Dim cMenu = new ContextMenu() Dim menuItem1 = new MenuItem() Dim menuItem2 = new MenuItem() menuItem1.Text = "Default Item 1" menuItem2.Text = "Default Item 2" ' Add menuItem2 as a child of menuItem1 menuItem1.MenuItems.Add(menuItem2) ' Add menuItem1 to the context menu cMenu.MenuItems.Add(menuItem1) ' Add the context menu to a label control label1.ContextMenu = cMenu
When a ContextMenu is invoked, a Popup event is fired. This event can be handled to customize the ContextMenu before it is shown to the user. When a MenuItem is selected from the ContextMenu, a Click event is fired for the MenuItem. Listing 3.3 demonstrates how to handle both events:
Listing 3.3
C#
private void contextMenu1_Popup(object sender, System.EventArgs e) {
this.contextMenu1.MenuItems.Clear();
if(this.checkBox1.Checked)
this.contextMenu1.MenuItems.Add(this.menuItem1);
if(this.checkBox2.Checked)
this.contextMenu1.MenuItems.Add(this.menuItem2);
if(this.checkBox3.Checked)
this.contextMenu1.MenuItems.Add(this.menuItem3);
// Always add the default menu
this.contextMenu1.MenuItems.Add(this.menuItem4);
}
private void menuItem1_Click(object sender, System.EventArgs e) {
MessageBox.Show("You selected MenuItem 1");
}
private void menuItem2_Click(object sender, System.EventArgs e) {
MessageBox.Show("You selected MenuItem 2");
}
private void menuItem5_Click(object sender, System.EventArgs e) {
MessageBox.Show("You selected MenuItem 3");
}
private void menuItem3_Click(object sender, System.EventArgs e) {
MessageBox.Show("You selected MenuItem 3");
}
private void menuItem5_Click_1(object sender, System.EventArgs e) {
MessageBox.Show("You selected Default Item 2");
}
VB
Private Sub _
contextMenu1_Popup(ByVal sender As Object,
ByVal e As System.EventArgs) _Handles contextMenu1.Popup
contextMenu1.MenuItems.Clear()
If checkBox1.Checked Then
contextMenu1.MenuItems.Add(menuItem1)
If checkBox2.Checked Then
contextMenu1.MenuItems.Add(menuItem2)
End If
If checkBox3.Checked Then
contextMenu1.MenuItems.Add(menuItem3)
End If
' Always add the default menu
contextMenu1.MenuItems.Add(menuItem4)
End If
End Sub
Private Sub menuItem1_Click(ByVal sender As Object,
ByVal e As System.EventArgs) _Handles menuItem1.Click
MessageBox.Show("You selected MenuItem 1")
End Sub
Private Sub menuItem2_Click(ByVal sender As Object,
ByVal e As System.EventArgs) _Handles menuItem2.Click
MessageBox.Show("You selected MenuItem 2")
End Sub
Private Sub menuItem3_Click(ByVal sender As Object,
ByVal e As System.EventArgs) _Handles menuItem3.Click
MessageBox.Show("You selected MenuItem 3")
End Sub
Private Sub menuItem4_Click(ByVal sender As Object,
ByVal e As System.EventArgs) _Handles menuItem4.Click
MessageBox.Show("You selected MenuItem 4")
End Sub
Private Sub menuItem5_Click(ByVal sender As Object,
ByVal e As System.EventArgs) _Handles menuItem5.Click
MessageBox.Show("You selected MenuItem 5")
End Sub
Figure 3.20 shows an application running that uses a ContextMenu control. The MenuItems on the control are configured when it is activated. The CheckBox controls determine which MenuItems will be displayed. The Default Item 1 menu is always displayed. You will find the code for this sample in the code listings for this book.
)
Figure
3.20 An application that showcases the ContextMenu control running
on the Pocket PC 2002 emulator.