private void ComboBoxSet() { cb_Add_Useable.Items.Clear(); cb_Add_Manufact.Items.Clear(); cb_Update_Useable.Items.Clear(); cb_Update_Manufact.Items.Clear(); List <String> list = _SI.GetDefualtCode("divisionofmachine"); if (list != null) { foreach (string str in list) { cb_Add_Manufact.Items.Add(str); } foreach (string str in list) { cb_Update_Manufact.Items.Add(str); } list.Clear(); } list = _SI.GetDefualtCode("brandofmachine"); if (list != null) { foreach (string str in list) { cb_Add_Useable.Items.Add(str); } foreach (string str in list) { cb_Update_Useable.Items.Add(str); } list.Clear(); } }