hiding grids using ESC key

Question

I'm new to WPF. I have like 15 grids on my Window and I have a small menu on which I can click and choose which grid to show up or hide. One grid at a time only. I would like that grid to hode (fade out) when I hit Esc. I have all the animations already, I just need to know what grid is visible (active) at the moment.

I don't know how to get current topmost control of my Window.

My solution is when KeyDown event is triggered on my Window to:

private void Window_KeyDown(object sender, System.Windows.Input.KeyEventArgs e)
    {
        if (e.Key == System.Windows.Input.Key.Escape)
        {
            //check all grids for IsVisible and on the one that is true make 
            BeginStoryboard((Storyboard)this.FindResource("theVisibleOne_Hide"));
        }

    }

Answer 1

By active, I assume that means the one that has keyboard focus. If so, the following will return the control that currently has keyboard input focus:

System.Windows.Input.Keyboard.FocusedElement

You could use it like this:

if (e.Key == System.Windows.Input.Key.Escape)
{
    //check all grids for IsVisible and on the one that is true make 
    var selected = Keyboard.FocusedElement as Grid;
    if (selected == null) return; 

    selected.BeginStoryboard((Storyboard)this.FindResource("HideGrid"));
}

An approach that would be more decoupled would be to create a static attached dependency property. It could be used like this (untested):

<Grid local:Extensions.HideOnEscape="True" .... />

A very rough implementation would look like:

public class Extensions
{
    public static readonly DependencyProperty HideOnEscapeProperty = 
       DependencyProperty.RegisterAttached(
           "HideOnEscape", 
           typeof(bool), 
           typeof(Extensions), 
           new UIPropertyMetadata(false, HideOnExtensions_Set));

    public static void SetHideOnEscape(DependencyObject obj, bool value)
    {
        obj.SetValue(HideOnEscapeProperty, value);
    }

    public static bool GetHideOnEscape(DependencyObject obj)
    {
        return (bool)obj.GetValue(HideOnEscapeProperty);
    }

    private static void HideOnExtensions_Set(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var grid = d as Grid;
        if (grid != null)
        {
            grid.KeyUp += Grid_KeyUp;
        }
    }

    private static void Grid_KeyUp(object sender, KeyEventArgs e)
    {
        // Check for escape key...
        var grid = sender as Grid;
        // Build animation in code, or assume a resource exists (grid.FindResource())
        // Apply animation to grid
    }
}

This would remove the need to have code in codebehind.