In this article we will learn how to use TextBox KeyDown event handler in WPF using VB.NET.
KeyDown event
KeyDown event fires when we enter the Key of
the keyboard. In WPF TextBox control We use the KeyDown Event and the Key
property of e the KeyEventArgs, comparing it to Key.
For example
Drag and drop two TextBlock one TextBox on the
form.
Figure 1.
XAML code
<Window
x:Class="MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow"
Height="350"
Width="525">
<StackPanel>
<TextBlock
Width="300"
Height="20"
Background="Aqua"
Foreground="Maroon">
Type some text into the TextBox and press the Enter key.
</TextBlock>
<TextBox
Width="300"
Height="30"
Name="textBox1"
KeyDown="OnKeyDownHandler"
Background="DarkGreen"
Foreground="MediumOrchid" />
<TextBlock
Width="300"
Height="75"
Name="textBlock1"
Background="DarkOrange"
/>
</StackPanel>
</Window>
Now select textBox control and Press F4 for
KeyDown event.
Figure 2.
Now double click on the KeyDown event and add
the following code.
Private Sub OnKeyDownHandler(ByVal
sender As Object,
ByVal e As KeyEventArgs)
If e.Key = Key.[Return]
Then
textBlock1.Text = "You Entered: "
+ textBox1.Text
End If
End Sub
we can also set integer number according to key.
Private Sub OnKeyDownHandler(ByVal
sender As Object,
ByVal e As KeyEventArgs)
If e.Key = 6 Then
textBlock1.Text = "You Entered: "
+ textBox1.Text
End If
End Sub
Now run the application and test it.
Figure 3.
Now enter some text into the TextBox.
Figure 4.
Now press enter key.
Figure 5.