Adding the Control to the Toolbox
Now that your control has been compiled and you have a Web Forms page ready to test it, you can add the control to the Toolbox so it will be readily available for use.
To add your control to the Toolbox
On the Tools menu, click Add/Remove Toolbox Items.
On the .NET Framework Components tab of the Customize ToolBox dialog box, click the Browse button. Find CustomLabel.dll, select it, and click Open to add WebCustomControl1 to the list of components in the Customize Toolbox dialog box.
Select WebCustomControl1 in the list of .NET Framework components and click OK. WebCustomControl1 is added to the Toolbox.
When you are finished, you should see an icon on the toolbar that looks like this: