connection string problem

Question

friends in my application when i use following connection string while doing set up project in windows forms it running successfully on each and every PC

Data Source=.\\SQLEXPRESS;AttachDbFilename=" +Application.StartupPath + "\\dm\\hm.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True

but same connection string when i use in class library which is a data acces layer it is not working please suggest me comparitive connection string

Subhendu De · Answer

It is not working because you are referencing it from class library. Do one thing .... pass this string from windows form to class library or put the connectionstring in app.config file of the windows app.