如何获得DataGridTemplateColumn的底层(DataGridTemplateColumn)控件

Question

我使用这段代码将TextBox添加到DataGrid单元格中：(不，这里不能使用XAML )

Binding binding = new Binding("Fld_Company");
binding.Mode = BindingMode.OneWay;

FrameworkElementFactory frameworkElementFactory = new FrameworkElementFactory(typeof(TextBox));
DataTemplate dataTemplate = new DataTemplate();
dataTemplate.VisualTree = frameworkElementFactory;
frameworkElementFactory.SetBinding(TextBox.TextProperty, binding);

DataGridTemplateColumn dataGridTemplateColumn = new DataGridTemplateColumn();
dataGridTemplateColumn.IsReadOnly = true;
dataGridTemplateColumn.Header = "Company";
dataGridTemplateColumn.CellTemplate = dataTemplate;

this.dataGrid.Columns.Add(dataGridTemplateColumn);

我有办法在没有XAML的情况下获得底层的TextBox控件吗？

我试过的是：

• VisualTreeHelper，但GetChildrenCount()始终为0
• FindName，但我还没有找到合适的FrameworkElement

Answer 1

在研究了DataGrid一段时间之后，我发现我的问题没有任何意义。我上面的代码只准备了DataGrid，但没有填充任何数据。在此之前，不会生成任何行，因此无法找到underlying TextBox controls。

当DataGrid最终被数据填充时，获取底层控件的最佳方法似乎是捕捉LoadinRow事件。但是，当此事件触发时，行的加载仍未完成。需要临时分配第二个事件，在最后加载行时触发该事件。

{
    DataGrid.LoadingRow += DataGrid_LoadingRow;
}

private void DataGrid_LoadingRow(object sender, DataGridRowEventArgs e)
{
    // The visual tree is not built until the row is "loaded". This event fires when this happend:
    e.Row.Loaded += DataGrid_Row_Loaded;
}

private void DataGrid_Row_Loaded(object sender, RoutedEventArgs e)
{
    DataGridRow dataGridRow = (DataGridRow)sender;
    // important: Remove the event again
    dataGridRow.Loaded -= DataGrid_Row_Loaded;

    NestedGridFieldProperty ngrProp = (NestedGridFieldProperty)dataGridRow.Item;

    // Get the "presenter", which contains the cells
    DataGridCellsPresenter presenter = coNeboTools.ConeboMisc.GetVisualChild<DataGridCellsPresenter>(dataGridRow);

    // Get the cells in the presenter
    var cells = GetVisualChildren<DataGridCell>(presenter);

    // Get the underlying TextBox in column 0
    TextBox underlyingTextBox = (TextBox)cells.ElementAt(0).Content;

    // the Item property of the row contains the row data
    var myData = dataGridRow.Item;

    // do what ever is needed with the TextBlock
    underlyingTextBox.Foreground = Brushes.Red;
}

    // Static helper method to handle the visual tree
    public static IEnumerable<T> GetVisualChildren<T>(DependencyObject dependencyObject)
           where T : DependencyObject
    {
        if (dependencyObject != null)
        {
            int childrenCount = VisualTreeHelper.GetChildrenCount(dependencyObject);

            for (int i = 0; i < childrenCount; i++)
            {
                DependencyObject child = VisualTreeHelper.GetChild(dependencyObject, i);
                if (child != null && child is T)
                {
                    yield return (T)child;
                }

                foreach (T childOfChild in GetVisualChildren<T>(child))
                {
                    yield return childOfChild;
                }
            }
        }
    }

    // Static helper method to handle the visual tree
    public static childItem GetVisualChild<childItem>(DependencyObject obj)
        where childItem : DependencyObject
    {
        foreach (childItem child in GetVisualChildren<childItem>(obj))
        {
            return child;
        }

        return null;
    }