c# - WPF- 将更改事件添加到自动生成的 DataGridComboBoxColumn

Question

我有一个数据网格，在 DataGrid.AutoGeneratingColumn 事件中，我将一些列更改为 DataGridComboBoxColumns。

与此同时，我还想向该新组合框添加一个选择更改事件，但不知道如何访问 DataGridComboBoxColumn 中的组合框控件。

    private void dgGrid_AutogeneratingColumns(object sender, DataGridAutoGeneratingColumnEventArgs e)
    {
        var cb = new DataGridComboBoxColumn();
        switch (e.PropertyName)
        {
            case "name":

                using (Entities context = new Entities())
                {
                    List<object> fNames = (from x in context.view
                        select new object {objectname = x.objectname}).ToList<object>();

                    cb.Header = "xxx";
                    cb.ItemsSource = xxx;
                    cb.SelectedItemBinding = new Binding("xxx");
                    e.Column = cb;

                    //Get reference to combobox in this new column
                    //Add event to it
                    //?????

                }
                break;
            //more ....
        }
    }

Answer 1

您不能从 DataGrid.AutoGeneratingColumn 事件处理程序访问 ComboBox 实例，因为 ComBox 仅在该列的单元格进入编辑模式时创建，并且每次该单元格进入编辑模式时都会创建新的 ComboBox 实例。

这是一个示例代码，如何通过 DataGridComboBoxColumn.EditingElementStyle 执行您想要的操作通过设置属性 EventSetter对于 Selector.SelectionChangedEvent (ComboBox继承自Selector):

private void dgGrid_AutogeneratingColumns(object sender, DataGridAutoGeneratingColumnEventArgs e)
{
    switch (e.PropertyName)
    {
        case "name":

            var cb = new DataGridComboBoxColumn();

            // Old...
            cb.Header = "Name";
            cb.ItemsSource = new List<string>() { "Option1", "Option2", "Option3" };
            cb.SelectedItemBinding = new Binding("name");

            // NEW
            cb.EditingElementStyle = new Style(typeof(ComboBox))
            {
                Setters =
                {
                    new EventSetter(Selector.SelectionChangedEvent, new SelectionChangedEventHandler(OnComboBoxSelectionChanged))
                }
            };

            e.Column = cb;
            break;
    }
}

private static void OnComboBoxSelectionChanged(object sender, SelectionChangedEventArgs e)
{
    // We must check that both RemovedItems and AddedItems are not empty,
    // because this event also fires when ComboBox is initialized (when entering edit mode), but then RemovedItems is empty.
    if (e.RemovedItems.Count > 0 && e.AddedItems.Count > 0)
    {
        var newlySelectedName = (string)e.AddedItems[0];
    }
}