The SelectCommand property has not been initialized before calling 'Fill'. in WinForm

You have to specify select command of SqlDataAdapter before filling your table. You are not doing it. Your SqlCommand object is not connected in any way to your SqlDataAdapter.

 adp.SelectCommand=cmd;

Another way to accomplish would be to simply pass the SQLCommand as an argument into your data adapter as follows -

SqlCommand cmd = new SqlCommand();
SqlDataAdapter adp = new SqlDataAdapter(cmd);