Datagridview上的ComboBoxColumn中的「SelectedIndexChanged」事件

Question

我想在DataGridViewComboBoxColumn上處理此事件「SelectedIndexChanged」， 並將其設置爲gridview的「EditingControlShowing」事件。

問題： 「SelectedIndexChanged」事件在第一次嘗試從組合框中選擇項目時未觸發，但在第二次選擇該項目後，事件被觸發並且一切正常！

下面是代碼：

private void dgvRequest_EditingControlShowing(object sender, 
    DataGridViewEditingControlShowingEventArgs e) 
{ 
    ComboBox combo = e.Control as ComboBox; 

    if (combo != null) 
    { 
     if (dgvRequest.CurrentCell.ColumnIndex == col_ConfirmCmb.Index) 
     { 
      combo.SelectedIndexChanged -= combo_ConfirmSelectionChange; 
      combo.SelectedIndexChanged += combo_ConfirmSelectionChange; 

      return; 
     } 
    } 
} 


void combo_ConfirmSelectionChange(object sender, EventArgs e) 
{ 
    if (dgvRequest.CurrentCell.ColumnIndex != col_ConfirmCmb.Index) return; 

    ComboBox combo = sender as ComboBox; 
    if (combo == null) return; 

    MessageBox.Show(combo.SelectedText);// returns Null for the first time 
} 

Answer 1

事情變得複雜，因爲它們僅具有所有行一個編輯控制優化DataGridView的。下面是我如何處理類似的情況：

第一鉤了一個代表到EditControlShowing事件：

myGrid.EditingControlShowing += new DataGridViewEditingControlShowingEventHandler(
            Grid_EditingControlShowing); 
... 

然後在處理程序掛接到EditControl的SelectedValueChanged事件：

void Grid_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e) 
{ 
    ComboBox combo = e.Control as ComboBox; 
    if (combo != null) 
    { 
     // the event to handle combo changes 
     EventHandler comboDelegate = new EventHandler(
      (cbSender, args) => 
      { 
       DoSomeStuff(); 
      }); 

     // register the event with the editing control 
     combo.SelectedValueChanged += comboDelegate; 

     // since we don't want to add this event multiple times, when the 
     // editing control is hidden, we must remove the handler we added. 
     EventHandler visibilityDelegate = null; 
     visibilityDelegate = new EventHandler(
      (visSender, args) => 
      { 
       // remove the handlers when the editing control is 
       // no longer visible. 
       if ((visSender as Control).Visible == false) 
       { 
        combo.SelectedValueChanged -= comboDelegate; 
        visSender.VisibleChanged -= visibilityDelegate; 
       } 
      }); 

     (sender as DataGridView).EditingControl.VisibleChanged += 
      visibilityDelegate; 

    } 
}