Datagridview 上 ComboBoxColumn 中的“SelectedIndexChanged”事件

Question

我想在 DataGridViewComboBoxColumn 上处理此事件“SelectedIndexChanged”， 我将它设置在 gridview 的“EditingControlShowing”事件上。

问题： 第一次尝试从组合框中选择项目时不会触发“SelectedIndexChanged”事件，但在第二次选择该项目后会触发该事件并且一切正常！

代码如下：

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，因为他们优化了 DataGridView，只为所有行设置了一个编辑控件。以下是我处理类似情况的方法：

首先将委托连接到 EditControlShowing 事件：

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

然后在处理程序中，连接到 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;

    }
}