Need help in how to add master page reference to a web form

Question

Hi,

 

I need your help in add master page reference to a normal web form in asp.net.

 

This is my Master Page: -

 

 

Solution Explorer look like :-

 

I did some code to add the master page reference to the normal web form, but not working and getting an error. Here the Normal form where I want to add master page reference :-