how can i type in combox and search a name and list

Connection obj = new Connection();
obj.getconn();
SqlCommand cmd3 = new SqlCommand();
cmd3.Connection = obj.con;
cmd3.CommandType = CommandType.StoredProcedure;
cmd3.CommandText = "SEL_Subcontractor1";
SqlDataAdapter ds3 = new SqlDataAdapter(cmd3);
cmd3.Parameters.AddWithValue("@name", sub.Text);
DataTable dt3 = new DataTable();
ds3.Fill(dt3);
sub.DataSource = dt3;
sub.DisplayMember = "name";
//sub.ValueMember = "subid";
obj.con.Close();
sub.AutoCompleteMode = AutoCompleteMode.Suggest;
sub.AutoCompleteSource = AutoCompleteSource.ListItems;
this is my code....combobox style is dropdown....
how can i type...
yes

its windows application