Create a control in Resources and reuse it in XAML WPF

Question

I just try to create a simple Symbol/Geometry/Control and change and reuse it in several places in the same window.

Example: a black square with a circle in the midd

Answer 1

When you define a arbitrary Control in Resources, you can use it in the future in Control which have property Content and derived from Control class. These are the followings: ContentControl, Label, ContentPresenter, etc.

Also you must set x:Shared="False" for resource if you want to use this resource in many Controls, because x:Shared="True" by default then one Resource is common to all - in this case, the system swears on the duplicate Content. When x:Shared="False" when is created Resource for each element whenever it its request. Quote from MSDN:

When set to false, modifies WPF resource-retrieval behavior so that requests for the attributed resource create a new instance for each request instead of sharing the same instance for all requests.

Example:

To change the Fill of Ellipse in code-behind, you can like this:

private void ChangeBackground_Click(object sender, RoutedEventArgs e)
{
    var canvas = MyContentControl.Content as Canvas;

    if (canvas != null)
    {
        foreach (var item in canvas.Children)
        {
            if (item is Ellipse)
            {
                ((Ellipse)item).Fill = Brushes.Green;
            }
        }
    }
}