ASP.NET in a Nutshell

Name

ControlDesigner

Synopsis

This is base class for web control designers like System.Web.UI.Design.WebControls.AdRotatorDesigner. These designers create the design-time appearance that a control provides to the design editor (like Visual Studio .NET). This HTML code is provided through the GetDesignTimeHtml() method, which is called by the host. The base implementation of the GetDesignTimeHtml() method invokes the System.Web.UI.Control.Render() method of the appropriate control to create the same HTML at design time as at runtime. A custom designer modifies this behavior by overriding the GetDesignTimeHtml() to provide HTML that is more suitable for a design-time representation.

You can create your own custom designer to use with a custom System.Web.UI.WebControls.WebControl. In this case, you use the System.ComponentModel.DesignerAttribute on the class declaration of your control to connect it with the appropriate designer. You can set various ControlDesigner properties—the most useful of which is AllowResize, which restricts your control to a fixed size. When your control is resized, the designer will call corresponding methods like OnControlResize() to give you a chance to refresh the appearance of your control accordingly.

The GetDesignTimeHtml() method should call GetEmptyDesignTimeHtml() if the rendered HTML string is empty (for example, when required control properties are not set). The base implementation of GetEmptyDesignTimeHtml() returns the fully qualified name of ...