How do you find which class belongs to which DLL ?

I am new to .NET dev and I cut and paste a lot of code. One strugel i have is when I I use a class name, I need to find out what I need to add in the reference (using clause at the top) and what DLL to use. Is their a easy way to find out what class is on what DLL. My pc is littered with 500 - 600 .NET dll.


Jay




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