WPF 后台创建 DateTemplate

在 WPF 编程中，我们通常都是在前台 XAML 中通过标记语言来编写 DataTemplate 的。曾今有小伙伴在 Stack Overflow 上提问，如何在后台通过 C# 代码来创建 DataTemplate ？我搜索了一番，找到了 FrameworkElementFactory 类，它便是生成 DataTemplate 的核心功臣。

先看一下 XAML 中实现的效果：

<Grid x:Name="RootGrid">
    <DataGrid x:Name="MyDataGrid" AutoGenerateColumns="False">
        <DataGrid.Columns>
            <DataGridTemplateColumn>
                <DataGridTemplateColumn.CellTemplate>
                    <DataTemplate>
                        <StackPanel Orientation="Horizontal">
                            <TextBlock Foreground="Red" Text="{Binding ValueA}"/>
                            <TextBlock Foreground="Blue" Text="{Binding ValueB}" />
                        </StackPanel>
                    </DataTemplate>
                </DataGridTemplateColumn.CellTemplate>
            </DataGridTemplateColumn>
        </DataGrid.Columns>
    </DataGrid>
</Grid>

将 XAML 中的效果用 C# 来实现：

public MainWindow()
{
    InitializeComponent();
    InitializeDataGrid();
}

private void InitializeDataGrid()
{
    // StackPanel and Children
    var stackPanelFactory = new FrameworkElementFactory(typeof(StackPanel));
    stackPanelFactory.SetValue(StackPanel.OrientationProperty, Orientation.Horizontal);

    var textBlockFactoryA = new FrameworkElementFactory(typeof(TextBlock));
    textBlockFactoryA.SetValue(TextElement.ForegroundProperty, Brushes.Red);
    textBlockFactoryA.SetBinding(TextBlock.TextProperty, new Binding("ValueA"));

    var textBlockFactoryB = new FrameworkElementFactory(typeof(TextBlock));
    textBlockFactoryB.SetValue(TextElement.ForegroundProperty, Brushes.Blue);
    textBlockFactoryB.SetBinding(TextBlock.TextProperty, new Binding("ValueB"));

    stackPanelFactory.AppendChild(textBlockFactoryA);
    stackPanelFactory.AppendChild(textBlockFactoryB);

    // DataTemplate
    var dataTemplate = new DataTemplate
    {
        VisualTree = stackPanelFactory
    };

    // DataGridTemplateColumn
    var templateColumn = new DataGridTemplateColumn
    {
        CellTemplate = dataTemplate
    };

    _dataGrid.Columns.Add(templateColumn);

    // DataGrid
    _dataGrid.Name = "MyDataGrid";
    _dataGrid.AutoGenerateColumns = false;

    // Add the DataGrid into RootGrid
    RootGrid.Children.Add(_dataGrid);
}

private readonly DataGrid _dataGrid = new DataGrid();