Custom Controls: Add custom button click logic within a custom control

Question

I am creating an on-screen keyboard Custom Control that sends text to a target TextBox . Inside this keyboard, I am laying out custom KeyboardKey button controls that have an associated text output or keyboard keypress (Backspace, Arrow Keys, etc.).

Currently, I have defined a bunch of different controls and hard-coded their Click functionality inside of the control template:

public override void OnApplyTemplate()
{
    base.OnApplyTemplate();
    Click += (s, e) =>
    {
        keyboard.Target.Focus(); // Focus on parent keyboard's TextBox
        /* Key press logic, e.g. send character output or execute key press */
    };
}

But I was wondering if I couldn't do it in a more organised way. I watched this tutorial about routed events to work with custom ICommand s but unfortunately I couldn't make it work in a custom control. (Until mm8 pointed out a way to do it after all)

Answer 1

You could create a custom class and add dependency properties to it. Something like this:

public class CustomButton : Button
{
    public static readonly DependencyProperty SomeCommandProperty = 
        DependencyProperty.Register(nameof(SomeCommand), typeof(ICommand), typeof(CustomButton));

    public ICommand SomeCommand
    {
        get { return (ICommand)GetValue(SomeCommandProperty); }
        set { SetValue(SomeCommandProperty, value); }
    }

    protected override void OnClick()
    {
        base.OnClick();
        //do something based on the property value...
        if (SomeCommand != null)
            SomeCommand.Execute(null);
    }
}

You could then set the dependency properties everywhere where you use the control, eg:

<local:CustomButton Command="{Binding SomeCommand}" />