Friend and Protected Friend Function::::::::::::::::::::::::::::::::
Friend and Protected Friend are nothing but Internal and Protected Internal in C#......., its that way in VB.NET

User Contrls vs Custom Controls:::::::::::::::::::::::::::
The main difference between the two controls lies in ease of creation vs. ease of use at design time.
Web user controls are easy to make, but they can be less convenient to use in advanced scenarios. Web user controls can be developed almost exactly the same way that you develop Web Form pages.

Like Web Forms, user controls can be created in the visual designer or they can be written with code separate from the HTML. They can also support execution events. However, since Web user controls are compiled dynamically at run time they cannot be added to the Toolbox and they are represented by a simple placeholder when added to a page.

This makes Web user controls harder to use if you are accustomed to full Visual Studio .NET
design-time support, including the Properties window and Design view previews. Also the only way to share the user control between applications is to put a separate copy in each application, which takes more maintenance if you make changes to the control.

Web custom controls are compiled code, which makes them easier to use but more difficult to create. Web custom controls must be authored in code. Once you have created the control you can add it to the Toolbox and display it in a visual designer with full Properties window support and all the other design-time features of ASP.NET server controls. In addition you can install a single copy of the Web custom control in the global assembly cache and share it between applications, which make maintenance easier