XamlReader解析后恢复绑定

Question

我的问题是:在我的程序中，我让用户在画布上放置形状(类DrawingShape)。绘图形状封装了堆叠的路径和标签：

<UserControl x:Class="HandballTrainerFluent.Graphics.DrawingShape"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             mc:Ignorable="d"
             d:DesignHeight="60"
             d:DesignWidth="60"
             DataContext="{Binding RelativeSource={RelativeSource Self}}">
    <Grid x:Name="container" Width="Auto" Height="Auto">
        <Grid.RowDefinitions>
            <RowDefinition Height="38"/>
            <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>
        <Canvas x:Name="geometryCanvas" HorizontalAlignment="Center" Grid.Row="0" Width="38" Height="38">
            <Path x:Name="Path"
                  Width="35.8774"
                  Height="31.2047"
                  Canvas.Left="1.0613"
                  Canvas.Top="3.29528"
                  Stretch="Fill"
                  StrokeLineJoin="Round"
                  Stroke="{Binding OutlineBrush,Mode=OneWay}"
                  StrokeThickness="{Binding OutlineWidth,Mode=OneWay}"
                  StrokeDashArray="{Binding OutlinePattern,Mode=OneWay}"
                  Fill="{Binding FillBrush,Mode=OneWay}"
                  Data="F1 M 19,3.79528L 1.5613,34L 36.4387,34L 19,3.79528 Z "/>
        </Canvas>
        <TextBlock x:Name="TextBox" HorizontalAlignment="Center" Grid.Row="1" Text="{Binding LabelText,Mode=OneWay}"></TextBlock>
    </Grid>
</UserControl>

因此，一些可视设置和标签文本绑定到代码隐藏文件的属性。

在用这些绘图形状反序列化画布之后，我需要恢复XAML和代码隐藏文件之间的绑定。我试过了，但似乎行不通：

private void RepairBindingsAfterLoading()
{
    foreach (UIElement element in this.drawingCanvas.Children)
    {
        if (element.GetType() == typeof(DrawingShape))
        {
            DrawingShape shape = (DrawingShape)element;
            BindingOperations.ClearAllBindings(shape.Path);
            BindingOperations.ClearAllBindings(shape.TextBox);
            BindingOperations.ClearAllBindings(shape);

            shape.BeginInit();
            Binding dataContextBinding = new Binding();
            dataContextBinding.RelativeSource = RelativeSource.Self;
            shape.SetBinding(DrawingShape.DataContextProperty, dataContextBinding);

            Binding fillBinding = new Binding("FillBrush");
            shape.Path.SetBinding(Path.FillProperty, fillBinding);
            Binding outlineBinding = new Binding("OutlineBrush");
            shape.Path.SetBinding(Path.StrokeProperty, outlineBinding);
            Binding widthBinding = new Binding("OutlineWidth");
            shape.Path.SetBinding(Path.StrokeThicknessProperty, widthBinding);
            Binding patternBinding = new Binding("OutlinePattern");
            shape.Path.SetBinding(Path.StrokeDashArrayProperty, patternBinding);

            Binding labelTextBinding = new Binding("LabelText");
            shape.TextBox.SetBinding(TextBlock.TextProperty, labelTextBinding);
            shape.EndInit();
            shape.UpdateLayout();
        }
    }
}

无论我对代码隐藏属性(例如，更改FillBrush)做了什么，显示的DrawingShape的可视化都不会更新。我是不是错过了重要的一步？

在看到这个问题后，我添加了shape.BeginUpdate()和shape.EndUpdate()：Bindings not applied to dynamically-loaded xaml

非常感谢你的见解

编辑2012-09-25

查看另一段不依赖于任何绑定的代码，我想知道，我是否能够通过x:Name反序列化引用Xaml-定义中的任何元素。以下回调不会对形状执行任何操作：

private void rotateClockwiseMenuItem_Click(object sender, RoutedEventArgs e)
{
    if(this.drawingCanvas.SelectedItem.GetType() == typeof(DrawingShape))
    {
        DrawingShape shape = (DrawingShape)this.drawingCanvas.SelectedItem;
        TransformGroup transformStack = new TransformGroup();
        transformStack.Children.Add(shape.geometryCanvas.LayoutTransform);
        transformStack.Children.Add(new RotateTransform(90));
        shape.geometryCanvas.LayoutTransform = transformStack;
    }
}

调试告诉我，shape的内容似乎恰到好处。当我执行一次命令时，shape.geometryCanvas.LayoutTransform是标识矩阵。当第二次执行时，shape.geometryCanvas.LayoutTransform是两个元素的TransformGroup。

它看起来像是geometryCanvas的引用(在Xaml中声明)并不是屏幕上使用的引用。

Answer 1

明白了!

我不知道您不能成功地在反序列化之后从代码隐藏文件外部引用x:Name'd XAML元素(这似乎是当前的问题)。

解决方案之一是在FindName()上使用UserControl，例如：

TextBlock textBox = shape.FindName("TextBox") as TextBlock;

完整和正确的RepairBindingsAfterLoading()如下所示：

private void RepairBindingsAfterLoading()
{
    foreach (UIElement element in this.drawingCanvas.Children)
    {
        if (element.GetType() == typeof(DrawingShape))
        {
            DrawingShape shape = (DrawingShape)element;
            shape.DataContext = shape;

            Path path = shape.FindName("Path") as Path;
            Binding fillBinding = new Binding("FillBrush");
            path.SetBinding(Path.FillProperty, fillBinding);
            Binding outlineBinding = new Binding("OutlineBrush");
            path.SetBinding(Path.StrokeProperty, outlineBinding);
            Binding widthBinding = new Binding("OutlineWidth");
            path.SetBinding(Path.StrokeThicknessProperty, widthBinding);
            Binding patternBinding = new Binding("OutlinePattern");
            path.SetBinding(Path.StrokeDashArrayProperty, patternBinding);

            TextBlock textBox = shape.FindName("TextBox") as TextBlock;
            Binding labelTextBinding = new Binding("LabelText");
            textBox.SetBinding(TextBlock.TextProperty, labelTextBinding);
        }
    }
}

只是为了记录下，我的笨拙

BindingOperations.ClearAllBindings(shape.Path);
BindingOperations.ClearAllBindings(shape.TextBox);
BindingOperations.ClearAllBindings(shape);

它的工作原理就像dbaseman建议的更简单、更优雅的解决方案：

shape.DataContext = this;

希望这能帮助别人避免我的错误:-)