Hi Jitendra,
I'm happy that it works now! 
"Any idea about the version from which version, no need to write the code "
Based on Sebastien's comment and the mentioned OSS note, you don't need this if you're on SP6:
"However, in order to activate the type-ahead on the dynpro side, you need the method cl_dsh_dynpro_properties=>enable_type_ahead() in a PBO module if you are running a NW 7.4 SP lower than 6."
Cheers,
Peter