database connection string

Question

I am working on a window form.....where i am creating  a database.

to connect in that database i need a connection string....

(Data Source=.\SQLEXPRESS;AttachDbFilename="c:\users\lipu\documents\visual studio 2010\Projects\marriage_book\marriage_book\giftdb.mdf";Integrated Security=True;User Instance=True )

 

while inserting the above string, it is showing some error.... what is wrong with the above string.