Difference between Custom Controls and User Controls.

Difference between Custom Controls and User Controls.

1.User Control is a page file with extension .ascx which can only be used withina single application. But custom controls are assemblies(dll files) that can be used in multiple applications.
2.User Controls cannot be added to the ToolBox of VS.NET . To use a user Control with in anaspx page u have to drag the user Control from the solution Explorer to designer page.But Custom Controls can be added to ToolBox of VS.NET.
3.User Controls can be viewed as a sort of generic controls during the design time.The proper GUI of user controls can be viewed only during the run time.But Custom Controls can be viewed during the design time.
4. User controls are created from existing Webserver and html server controls .But a developer who creates custom controls have to render every thing from the scratch.