Extended WPF Toolkit ColorPicker: How to use ContextMenu events?

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Situation: I have ColorPicker in Canvas.
Goal: To use events of ContextMenu.
Problem: The ContextMenuOpening event doesn't fire and the ContextMenu.Opened event results error as many other events.
Notes:
1. I mean a drop menu by "ContextMenu", but i don't know what "ContextMenu" exactly is.
2. It is Extended WPF Toolkit and to use it you need to add extended dlls.
Code:

C#

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();

        canvas.Background = Brushes.Black;
        this.Content = canvas;

        ColorPicker colorpicker = new ColorPicker();
        canvas.Children.Add(colorpicker);
        colorpicker.ContextMenuOpening += delegate { System.Windows.MessageBox.Show("a"); }; // Doesn't fire.
        colorpicker.ContextMenu.Opened += delegate { System.Windows.MessageBox.Show("a"); }; // Error: Object reference not set to an instance of an object.
    }

    Canvas canvas = new Canvas();
}

Posted 9-Oct-15 1:27am

Ziya1995

Updated 9-Oct-15 3:18am

v3

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Richard Deeming · Accepted Answer · 2015-10-09T03:45:00

A context menu is the menu that appears when you right-click on something. The color-picker's popup isn't a context menu, which is why the ContextMenuOpening event doesn't fire. And unless you've explicitly set the ContextMenu property, it will return null, which is why you're getting a NullReferenceException when you try to subscribe to it's Opened event.

Looking at the source code[^] for the ColorPicker control, it doesn't seem to fire an event when the popup opens. Your best bet is probably to subscribe to the property change event for the IsOpen property:

C#

DependencyPropertyDescriptor descriptor = DependencyPropertyDescriptor.FromProperty(ColorPicker.IsOpenProperty, typeof(ColorPicker));
descriptor.AddValueChanged(colorpicker, delegate 
{ 
    if (colorpicker.IsOpen)
    {
        // Do something here...
    }
});