WPF: Using a Virtual Keyboard

Question

I have created a virtual keyboard user control to use across multiple windows within my application. I am wondering how I am able to get it to input into a textbox in a window when a key is pressed.

What I am looking for is something like:

private void keyboardKey_Click(object sender, RoutedEventArgs e){
var key = sender as Button;
textbox.Text += key.Content;
}

So for example, if I press the key for 'a', then 'a' is added to the textbox.

My mind tends towards some sort of binding property but as I am new to WPF, I have no idea where to begin. Something like

<local:QWERTYKeyboard TextboxBinding="TextboxName"/>

Thanks

Answer 1

This is quite complicated task. Fortunately there's couple good tutorials on this subject.

I would recommend you to go through these two tutorials:

• A Software Virtual Keyboard for Your WPF Apps
• A Touch Screen Keyboard Control in WPF

Especially there first one should contain a sample app which should get you started.

For your particular question regarding getting the text into TextBox. One (naive) implementation is to track the focus .

Your virtual keyboard could have property which contains the currently focused TextBox:

public TextBox FocusedTextBox {get;set;}

And each of your app's textboxes could update the property based on the GotFocus-event:

private void txtBox_GotFocus(object sender, RoutedEventArgs e)
{
    // Set virtual keyboards' active textbox
    this.VirtualKeyboard.FocusedTextBox = txtBox;
}

Now in your Virtualkeyboard, when one presses "a", you can just update the content of the TextBox:

private void UserPressedVirtualKeyboard(object sender, RoutedEventArgs e)
{
    this.VirtualKeyboard.FocusedTextBox.Text = this.VirtualKeyboard.FocusedTextBox.Text + pressedChar;
}