ContentControl的精彩使用

先看效果

在WPF中ContentControl的Content属性是object，预示着它可以绑定任何类型，不管是View还是ViewModel都可以。
我们先看正确的代码

  <Window.Resources>
      <DataTemplate DataType="{x:Type viewModel:UniformGridViewModel}">
          <view:UniformGridView />
      </DataTemplate>
      <viewModel:UniformGridViewModel x:Key="UniformGridViewModel" />
      <view:UniformGridView x:Key="UniformGridView" />
  </Window.Resources>
  <Grid>
      <Grid.RowDefinitions>
          <RowDefinition Height="auto"/>
          <RowDefinition Height="auto"/>
          <RowDefinition Height="auto"/>
          <RowDefinition Height="auto"/>
      </Grid.RowDefinitions>
   <ContentControl Grid.Row="0" Content="{StaticResource UniformGridView}"/>
  <ContentControl Grid.Row="1" Content="{StaticResource UniformGridViewModel}"/>
  <ContentControl Grid.Row="2" Content="{Binding UniformGridView}" />
  <ContentControl Grid.Row="3" Content="{Binding UniformGridViewModel}" />
  </Grid>

    public class MainWindowViewModel : BindableBase
    {
        private UniformGridViewModel _uniformGridViewModel=new UniformGridViewModel();

        public UniformGridViewModel UniformGridViewModel
        {
            get => _uniformGridViewModel;
            set => SetProperty(ref _uniformGridViewModel, value);
        }

        private UniformGridView _uniformGridView=new UniformGridView();

        public UniformGridView UniformGridView
        {
            get => _uniformGridView;
            set => SetProperty(ref _uniformGridView, value);
        }
  
    }

<UserControl
    x:Class="DataContext另类绑定.Views.UniformGridView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:local="clr-namespace:DataContext另类绑定.Views"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:prism="http://prismlibrary.com/"
    d:DesignHeight="450"
    d:DesignWidth="800"
    prism:ViewModelLocator.AutoWireViewModel="True"
    mc:Ignorable="d">
    <Grid>
        <TextBlock Text="{Binding Name}" />
    </Grid>
</UserControl>

    public class UniformGridViewModel:BindableBase
    {
		private string _name;

		public string Name
		{
			get => _name;
			set => SetProperty(ref _name, value);
		}

        public UniformGridViewModel()
        {
            Name = "Hello";
        }
    }

可以看到我们使用了Prism框架，对UniformGridView使用了prism:ViewModelLocator.AutoWireViewModel="True"
按理来说，应该不用多此一举写

<DataTemplate DataType="{x:Type viewModel:UniformGridViewModel}">
     <view:UniformGridView />
</DataTemplate>

如果我们去掉会怎样

此时，只有

 <ContentControl Grid.Row="0" Content="{StaticResource UniformGridView}"/>
  <ContentControl Grid.Row="2" Content="{Binding UniformGridView}" />

是起作用的，
这是因为去掉DataTemplate后，只有直接使用StaticResource和Binding到UserControl的ContentControl显示正常，而Binding到ViewModel的ContentControl没有显示预期的UserControl。这是因为WPF不知道如何将ViewModel转换为UserControl。