Silverlight 3 - 数据绑定画布上矩形的位置 [英] Silverlight 3 - Data Binding Position of a rectangle on a canvas

问题描述

我正在尝试使用ItemsControl将一组对象绑定到Silverlight 3中的Canvas，如下所示：

I am currently trying to bind a collection of objects to a Canvas in Silverlight 3 using an ItemsControl as below:

<ItemsControl x:Name="ctrl" ItemsSource="{Binding myObjectsCollection}">
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <Canvas></Canvas>
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <Rectangle Stroke="LightGray" Fill="Black"  StrokeThickness="2" 
                   RadiusX="15" RadiusY="15" Canvas.Left="{Binding XAxis}"
                   Height="25" Width="25">
            </Rectangle>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>

不幸的是，似乎Canvas.Left上的绑定被忽略。从我所学到的这里将会出现这是由于项目被放置在内容演示者内，而不是我在项目面板中指定的实际画布。

Unfortunately it seems the binding on the Canvas.Left is being ignored. From what i have learned here it would appear this is due to the items being placed inside a content presenter not the actual canvas i have specified in the items panel.

有没有办法我可以使用数据绑定来确定元素的位置画布？

Is there a way i can use data binding to determine the position of elements on a canvas?

推荐答案

我意识到这已经有一个答案被接受了，但实现初始目标而不弄乱利润的方式是创建一个自定义的ItemsControl并覆盖PrepareContainerForItemOverride方法。在这种方法中，您可以在代码中设置绑定。

I realize that this already has an answer accepted, but the way to achieve the initial goal without messing with margins is to create a custom ItemsControl and override the PrepareContainerForItemOverride method. In this method, you set the binding in code.

public class CustomItemsCollection
    : ItemsControl
{
    protected override void PrepareContainerForItemOverride(DependencyObject element, object item)
    {

        FrameworkElement contentitem = element as FrameworkElement;
        Binding leftBinding = new Binding("Left"); // "Left" is the property path that you want to bind the value to.
        contentitem.SetBinding(Canvas.LeftProperty, leftBinding);

        base.PrepareContainerForItemOverride(element, item);
    }

}

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