根据类型选择数据模板

I've declared the following types:

我已经宣布了以下类型：

public interface ITest { }
public class ClassOne : ITest { }
public class ClassTwo : ITest { }

In my viewmodel I'm declaring and initializing the following collection:

在我的viewmodel中，我正在声明并初始化以下集合：

public class ViewModel
{
    public ObservableCollection<ITest> Coll { get; set; } = new ObservableCollection<ITest>
    {
        new ClassOne(),
        new ClassTwo()
    };  
}

In my view I'm declaring the following ItemsControl

在我看来，我正在声明以下ItemsControl

<ItemsControl ItemsSource="{Binding Coll}">
    <ItemsControl.Resources>
        <DataTemplate DataType="local:ClassOne">
            <Rectangle Width="50" Height="50" Fill="Red" />
        </DataTemplate>
        <DataTemplate DataType="local:ClassTwo">
            <Rectangle Width="50" Height="50" Fill="Blue" />
        </DataTemplate>
    </ItemsControl.Resources>
</ItemsControl>

What I expect to see is a red square followed by a blue square, instead what I see is the following:

我希望看到的是一个红色方块，后面是一个蓝色方块，而我所看到的是以下内容：

What am I doing wrong?

我究竟做错了什么？

2 个解决方案

#1

Your issue might be caused by finnicky workings of XAML. Specifically, you need to pass Type to DataType, but you were passing a string with the name of the type.

您的问题可能是由XAML的辛苦工作引起的。具体来说，您需要将Type传递给DataType，但是您传递的是具有该类型名称的字符串。

Use x:Type to decorate the value of DataType, like so:

使用x：Type来装饰DataType的值，如下所示：

<ItemsControl ItemsSource="{Binding Coll}">
    <ItemsControl.Resources>
        <DataTemplate DataType="{x:Type local:ClassOne}">
            <Rectangle Width="50" Height="50" Fill="Red" />
        </DataTemplate>
        <DataTemplate DataType="{x:Type local:ClassTwo}">
            <Rectangle Width="50" Height="50" Fill="Blue" />
        </DataTemplate>
    </ItemsControl.Resources>
</ItemsControl>

#2

You can also use DataTemplateSelector for that. MSDN ref. and * ref.

您也可以使用DataTemplateSelector。 MSDN参考和*参考。

#1