c# – Josh Smith MVVM演示应用

<HeaderedContentControl 
          Content="{Binding Path=Workspaces}"
          ContentTemplate="{StaticResource WorkspacesTemplate}"
          Header="Workspaces"
          Style="{StaticResource MainHCCStyle}"
          />

在资源中：

<DataTemplate x:Key="WorkspacesTemplate">
    <TabControl 
      IsSynchronizedWithCurrentItem="True" 
      ItemsSource="{Binding}" 
      ItemTemplate="{StaticResource ClosableTabItemTemplate}"
      Margin="4"
      />
  </DataTemplate>

在文章中说：

A typed DataTemplate does not have an x:Key value assigned to it,but
it does have its DataType property set to an instance of the Type
class. If WPF tries to render one of your ViewModel objects,it will
check to see if the resource system has a typed DataTemplate in scope
whose DataType is the same as (or a base class of) the type of your
ViewModel object. If it finds one,it uses that template to render the
ViewModel object referenced by the tab item’s Content property.

我的问题是：

模板如何知道类型是工作空间的集合(WorkspaceViewModel)？