Datagridview上的ComboBoxColumn中的“SelectedIndexChanged”事件

Question

我想在DataGridViewComboBoxColumn上处理此事件“SelectedIndexChanged”， 并将其设置为gridview的“EditingControlShowing”事件。

问题： “SelectedIndexChanged”事件在第一次尝试从组合框中选择项目时未触发，但在第二次选择该项目后，事件被触发并且一切正常！

下面是代码：

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

事情变得复杂，因为它们仅具有所有行一个编辑控制优化DataGridView的。下面是我如何处理类似的情况：

第一钩了一个代表到EditControlShowing事件：

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

然后在处理程序挂接到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; 

    } 
}