Hi

Take the Dll file of that Class and then 

Add it as a References in Another Website 

---Got solutions--->choose your folder -->add References---->and then select the Your Class Dll--

and then it will Add a Dll of your Class from another webapplication

Next got to your new Webpage codebehind file ---> write the name space of your dll(EX:using <dllName>)

then it will invoke all the functions that you wrote in dll class

Try this