How to create a KeyEventArgs object in WPF ( related to a SO answer )

Question

I\'ve found this answer which look like what I need:

How can I programmatically generate keypress events in C#?

Except for the fact I can\'t create an insta

Answer 1

var kea = new KeyEventArgs(
    Keyboard.PrimaryDevice,
    new HwndSource(0, 0, 0, 0, 0, "", IntPtr.Zero),
    0,
    Key.Enter)
    {
        RoutedEvent = UIElement.KeyUpEvent
    };

Answer 2

If anyone is trying to create the KeyEventArgs for use in a unit test you'll find that Keyboard.PrimaryDevice.ActiveSource is null.. and throws an exception when you try to use it.

Mocking a PresentationSource is a workable solution (requires sta):

[Test]
[RequiresSTA]
public void test_something()
{
  new KeyEventArgs(
    Keyboard.PrimaryDevice,
    new Mock<PresentationSource>().Object,
    0,
    Key.Back);
}

Answer 3

phewwww

I've found it: Keyboard.PrimaryDevice.ActiveSource has to be used

InputManager.Current.ProcessInput(
    new KeyEventArgs(Keyboard.PrimaryDevice,
        Keyboard.PrimaryDevice.ActiveSource,
        0, Key.Tab)
    {
       RoutedEvent = Keyboard.KeyDownEvent
    }
);

Answer 4

To unit test a viewmodel I had to use a combination of OscarRyz and Elijah W. Gagne answer to make this work.

    [TestMethod]
    public void method_event_expected()
    {
        this.objectUnderTest.TestMethod(
            new KeyEventArgs(Keyboard.PrimaryDevice, new HwndSource(0, 0, 0, 0, 0, "", IntPtr.Zero), 0, Key.Oem3)
            {
                RoutedEvent = Keyboard.KeyDownEvent
            });

        Assert.IsTrue(...)
    }

Keyboard.PrimaryDevice.ActiveSource was null so I had to fake it with a dummy window and then I also needed the RoutedEvent to be assigned.

Answer 5

Similar to Bill Tarbell's answer, you can also create a dummy System.Windows.Interop.HwndSource, like so:

var kea = new KeyEventArgs(
    Keyboard.PrimaryDevice, 
    new HwndSource(0, 0, 0, 0, 0, "", IntPtr.Zero), // dummy source
    0, 
    key);