Explain about Register directive's attributes ?

Answer:

There are 3 Register directive's attributes.They are:
1) TagPreFix
2) Namespace
3) Assembly

TagPreFix:
This TagPreFix name will identify the group to which the user control is belonged to.
Example:
The tag prefix for ASP.NET server controls is “asp”.
You can use this prefix for creating a naming convention to organize your custom controls.

Namespace:
This contains the controls that are to be registered within the custom control assembly.This is a project name within the custom control assembly.

Assembly:
It consists of the custom controls.This is the name of the assembly(.dll). The Web Application must refer the control assembly.Referencing the assembly maintains a copy of it in the Web application’s /bin directory.