Try:
AppDomain.CurrentDomain.SetData(
"DataDirectory", Path.Combine(AppDomain.CurrentDomain.BaseDirectory, ""));
This will Create Db File on /bin/Debug/yourdbname.mdf
Try:
AppDomain.CurrentDomain.SetData(
"DataDirectory", Path.Combine(AppDomain.CurrentDomain.BaseDirectory, ""));
This will Create Db File on /bin/Debug/yourdbname.mdf