＆QUOT;的SelectedIndexChanged＆QUOT;事件ComboBoxColumn上的DataGridView [英] "SelectedIndexChanged" event in ComboBoxColumn on Datagridview

问题描述

我想在DataGridViewComboBoxColumn处理此事件的SelectedIndexChanged 和我在GridView的EditingControlShowing事件设置。

问题： 的SelectedIndexChanged事件不触发从下拉框中选择一个项目的第一次尝试，但选择该项目第二次之后，事件被触发，一切工作正常！

下面是code：

 私人无效dgvRequest_EditingControlShowing（对象发件人，
     DataGridViewEditingControlShowingEventArgs五）
{
    组合框组合= e.Control为组合框;

    如果（组合！= NULL）
    {
        如果（dgvRequest.CurrentCell.ColumnIndex == col_ConfirmCmb.Index）
        {
            combo.SelectedIndexChanged  -  = combo_ConfirmSelectionChange;
            combo.SelectedIndexChanged + = combo_ConfirmSelectionChange;

            返回;
        }
    }
}


无效combo_ConfirmSelectionChange（对象发件人，EventArgs的）
{
    如果（dgvRequest.CurrentCell.ColumnIndex = col_ConfirmCmb.Index！）回报;

    组合框组合=发件人为组合框;
    如果（组合== NULL）回报;

    的MessageBox.show（combo.SelectedText）; //首次返回Null
}
 

解决方案

事情变得复杂，因为它们仅具有一个编辑控件中的所有行优化的DataGridView。以下是我处理过类似的情况：

先挂钩代表对EditControlShowing事件：

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

然后在处理程序挂接到EditControl的SelectedValueChanged事件：

 无效Grid_EditingControlShowing（对象发件人，DataGridViewEditingControlShowingEventArgs E）
{
    组合框组合= e.Control为组合框;
    如果（组合！= NULL）
    {
        //事件处理的组合变化
        事件处理程序comboDelegate =新的EventHandler（
            （cbSender，参数）=＆GT;
            {
                DoSomeStuff（）;
            }）;

        //注册的编辑控制事件
        combo.SelectedValueChanged + = comboDelegate;

        //因为我们不希望添加这个事件多次，当
        //编辑控制是隐藏的，我们必须消除我们添加了处理程序。
        事件处理程序visibilityDelegate = NULL;
        visibilityDelegate =新的EventHandler（
            （visSender，参数）=＆GT;
            {
                //删除处理程序时，编辑控件
                //不再可见。
                如果（（visSender作为对照）。可见= FALSE）
                {
                    combo.SelectedValueChanged  -  = comboDelegate;
                    visSender.VisibleChanged  -  = visibilityDelegate;
                }
            }）;

        （发件人为DataGridView中）.EditingControl.VisibleChanged + =
           visibilityDelegate;

    }
}
 

I want to handle this event "SelectedIndexChanged" on a DataGridViewComboBoxColumn, and I set it on "EditingControlShowing" event of the gridview.

The problem : "SelectedIndexChanged" event is not fired on first attempt of selecting an Item from the comboBox, but after selecting that item for the second time the event is fired and everything works fine !

Here is the code:

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
}

解决方案

Things get complicated since they optimized the DataGridView by only having one editing control for all the rows. Here's how I handled a similar situation:

First hook up a delegate to the EditControlShowing event:

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

Then in the handler, hook up to the EditControl's SelectedValueChanged event:

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;

    }
}

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