The overlay image is used to communicate information with a user about the state of an application. The C1TaskbarButtons overly icon can be set at design time in the Properties window or can be set via code for run time interaction. It is more common to see this property set when a specific event occurs at run time, but this topic will explain how to do it both ways.

In the Designer

In the Properties window, click the ellipses button next to the OverlayIcon and select your image from the Image dialog box.

In Code

Usually, you'll want to use an overlay icon in response to an application state, response, or event. The easiest thing to do is to add your preferred .ico file to the project as a resource or to use the existing system icons.

This example illustrates how to add an overlay icon to a simple Button_Click event using system icons.

To write code in Visual Basic

taskbarButton.OverlayIcon = New Icon(SystemIcons.[Error], 16, 16)

To write code in C#

taskbarButton.OverlayIcon = new Icon(SystemIcons.Error, 16, 16);

This example illustrates how to add an overlay icon to a simple Button_Click event using an embedded .ico resource named "Error".

To write code in Visual Basic

taskbarButton.OverlayIcon = Properties.Resources.[Error]

To write code in C#

taskbarButton.OverlayIcon = Properties.Resources.Error;