WPF アプリケーションの展開経験
1. You are creating a Windows Presentation Foundation application by using Microsoft .NET Framework
3.5.
You add a CommandBinding element to the Window element. The command has a keyboard gesture
CTRL+H. The Window contains the following MenuItem control.
<MenuItem Header=”Highlight Content”
Command=”local:CustomCommands.Highlight” />
You need to ensure that the MenuItem control is disabled and the command is not executable when the
focus shifts to a TextBox control that does not contain any text.
What should you do?
A. Set the IsEnabled property for the MenuItem control in the GotFocus event handler for the TextBox
controls.
B. Set the CanExecute property of the command to Highlight_CanExecute.
Add the following method to the code-behind file for the window.
Private Sub Highlight_CanExecute(ByVal sender As Object, _
ByVal e As CanExecuteRoutedEventArgs)
Dim txtBox As TextBox = CType(sender, TextBox)
e.CanExecute = (txtBox.Text.Length > 0)
End Sub
C. Set the CanExecute property of the command to Highlight_CanExecute.
Add the following method to the code-behind file for the window.
Private Sub Highlight_CanExecute(ByVal sender As Object, _
ByVal e As CanExecuteRoutedEventArgs)
Dim txtBox As TextBox
txtBox = CType(e.Source, TextBox)
e.CanExecute = (txtBox.Text.Length > 0)
End Sub
D. Set the CanExecute property of the command to Highlight_CanExecute.
Add the following method to the code-behind file for the window.
Private Sub Highlight_CanExecute(ByVal sender As Object, _
ByVal e As CanExecuteRoutedEventArgs)
Dim Menu As MenuItem = CType(e.Source, MenuItem)
Dim txtBox As TextBox = CType(Menu.CommandTarget, TextBox)
Menu.IsEnabled = (txtBox.Text.Length > 0)
End Sub
Answer: C
