How to make a UserControl object acts as a control container design-time by using Visual C#

This step-by-step article describes how to make a UserControl object act as a control container at design-time after you put the UserControl on a Windows Form. There may be situations where you want to drag a control to your UserControl. To do this, the UserControl must act as a control container.

Overview

By default, a UserControl object can act as a control container only when you create the control. To make a UserControl host a constituent control after you put the UserControl on a Windows Form, you must change the default designer of the UserControl. To implement design-time services for a component, use the DesignerAttribute class of the System.ComponentModel namespace. The DesignerAttribute comes before the class declaration. Initialize the DesignerAttribute by passing the designerTypeName and the designerBaseType parameters.

designerTypeName is the fully qualified name of the designer type that provides design-time services. Pass the combination of the System.Windows.Forms.Design.ParentControlDesigner and the System.Design for the designerTypeName parameter. The ParentControlDesigner class extends design-time behavior for a UserControl.

designerBaseType is the name of the base class for the designer. The class that is used for the design-time services must implement the IDesigner interface.

Create the UserControl as a Design-Time Control Container

1. Create a new Visual C# Windows Control Library project. To do this, follow these steps:
   1. Start Visual Studio.
   2. On the File menu, point to New, and then click Project.
   3. Under Project Types, click Visual C# , and then click Windows Forms Control Library under Templates.
      
      Note In Visual Studio 2003, click Visual C# Projects under Project Types and then click Windows Control Library under Templates.
2. Name the project ContainerUserControl. By default, UserControl1.cs is created.
3. In Solution Explorer, right-click UserControl1.cs, and then click View Code.
4. Add the following code to the Declarations section:

   using System.ComponentModel.Design;

5. Apply the System.ComponentModel.DesignerAttribute attribute to the control as follows:

   [Designer("System.Windows.Forms.Design.ParentControlDesigner, System.Design", typeof(IDesigner))] 
   public class UserControl1 : System.Windows.Forms.UserControl
   {
   
         ...
   
   }

6. On the Build menu, click Build Solution.

Test the UserControl

1. Create a new Visual C# project. To do this, follow these steps:
   1. Start Visual Studio.
   2. On the File menu, point to New, and then click Project.
   3. Under Project Types, click Visual C#, and then click Windows Forms Application under Templates. By default, Form1.cs is created.
      
      Note In Visual Studio 2003, click Visual C# Projects under Project Types, and then click Windows Control Library under Templates.
2. Add the UserControl1 control to the toolbox.
   1. On the Tools menu, click Choose Toolbox Items.
   2. On the .NET Framework Components tab, click Browse.
   3. In the Open File box, locate the DLL that was built when you created the UserControl control.
3. Drag UserControl1 from the toolbox (under Windows Forms) to Form1.cs.
4. Drag a Button control from the toolbox to UserControl1.
5. Notice that the UserControl1 behaves as control container for the Button control.

For more information, see the following Microsoft Web sites: