Trouble with Parameter!

Question

I'm having an error message sounding like :
Prepared statement '(@id text)SELECT * from isp_email.staff where @id like +txtname.' expects parameter @id, which was not supplied.
This message appear when I press button to select a row at run time. What could be the problem?
 
SqlCommand myCommand = new SqlCommand();
myCommand.Connection=con;
myCommand.CommandText="SELECT * from isp_email.staff where @id like +txtname.Text";
SqlParameter myparam = new SqlParameter("@id",SqlDbType.Text);
myparam.Value=ID;
myCommand.Parameters.Add(myparam);
SqlDataAdapter myAdapter=new SqlDataAdapter(myCommand);
DataSet ds = new DataSet();
myAdapter.Fill(ds);
con.Open();
myCommand.ExecuteNonQuery();
dgupdate.DataSource=ds;
dgupdate.DataBind();
con.Close();
Thank you.