如何以编程方式创建包含内容的datatemplate？

Question

我想在运行时在代码中执行以下操作:

<DataTemplate x:Key="lightGreenRectangle">
        <Rectangle Fill="LightGreen"/>
    </DataTemplate>

到目前为止我有:

public DataTemplate GetColouredRectangleInDataTemplate(Color colour)
{
    DataTemplate dataTemplate = new dataTemplate();

    return dataTemplate;
}

救命？我知道这不是设计控件样式的最优雅方式,但我想指定颜色的组件有一个名为"PointTemplate"的属性,类型为DataTemplate.

Answer 1

如果由于某种原因你需要以DataTemplate编程方式创建,你会做:

XAML:

<Grid x:Name="myGrid">
    <ContentControl ContentTemplate="{DynamicResource lightGreenRectangle}" />
</Grid>

代码中的某个地方:

    public static DataTemplate CreateRectangleDataTemplate()
    {
        var rectangleFactory = new FrameworkElementFactory(typeof(Rectangle));
        rectangleFactory.SetValue(Shape.FillProperty, new SolidColorBrush(System.Windows.Media.Colors.LightGreen));

        return new DataTemplate
                   {
                       VisualTree = rectangleFactory,
                   };
    }

    public static void AddRectangleTemplateToResources(FrameworkElement element)
    {
        element.Resources.Add("lightGreenRectangle", CreateRectangleDataTemplate());
    }

然后你只需要添加DataTemplate到一个ResourceDictionary所以它可以使用.例如,在后面的代码中:

    public MainWindow()
    {
        InitializeComponent();
        AddRectangleTemplateToResources(myGrid);
    }

希望这可以帮助!

Answer 2

使用以下帮助程序类:

/// <summary>
/// Class that helps the creation of control and data templates by using delegates.
/// </summary>
public static class TemplateGenerator
{
  private sealed class _TemplateGeneratorControl:
    ContentControl
  {
    internal static readonly DependencyProperty FactoryProperty = DependencyProperty.Register("Factory", typeof(Func<object>), typeof(_TemplateGeneratorControl), new PropertyMetadata(null, _FactoryChanged));

    private static void _FactoryChanged(DependencyObject instance, DependencyPropertyChangedEventArgs args)
    {
      var control = (_TemplateGeneratorControl)instance;
      var factory = (Func<object>)args.NewValue;
      control.Content = factory();
    }
  }

  /// <summary>
  /// Creates a data-template that uses the given delegate to create new instances.
  /// </summary>
  public static DataTemplate CreateDataTemplate(Func<object> factory)
  {
    if (factory == null)
      throw new ArgumentNullException("factory");

    var frameworkElementFactory = new FrameworkElementFactory(typeof(_TemplateGeneratorControl));
    frameworkElementFactory.SetValue(_TemplateGeneratorControl.FactoryProperty, factory);

    var dataTemplate = new DataTemplate(typeof(DependencyObject));
    dataTemplate.VisualTree = frameworkElementFactory;
    return dataTemplate;
  }

  /// <summary>
  /// Creates a control-template that uses the given delegate to create new instances.
  /// </summary>
  public static ControlTemplate CreateControlTemplate(Type controlType, Func<object> factory)
  {
    if (controlType == null)
      throw new ArgumentNullException("controlType");

    if (factory == null)
      throw new ArgumentNullException("factory");

    var frameworkElementFactory = new FrameworkElementFactory(typeof(_TemplateGeneratorControl));
    frameworkElementFactory.SetValue(_TemplateGeneratorControl.FactoryProperty, factory);

    var controlTemplate = new ControlTemplate(controlType);
    controlTemplate.VisualTree = frameworkElementFactory;
    return controlTemplate;
  }
}

您可以像这样创建数据模板:

DataTemplate template = 
  TemplateGenerator.CreateDataTemplate
  (
    () =>
    {
      var result = new TextBox()
      result.SetBinding(TextBox.TextProperty, "BindingPathHere");
      return result;
    }
  );

您可以自由地使用任何代码来创建控件,就像您在没有任何数据模板的情况下直接创建控件一样.有关详细信息,请参阅代码项目中的此提示:http://www.codeproject.com/Tips/808808/Create-Data-and-Control-Templates-using-Delegates