如何将模板中控件的命令绑定到ViewModel

<Window x:Class="WpfGettingThingsDone.View.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    AllowsTransparency="True"
    Background="Transparent"
    WindowStyle="None"    
    Title="{Binding Title}" Height="300" Width="300">
    <Window.Resources>
        <ResourceDictionary>
            <Style x:Key="WindowBorderBackground" TargetType="{x:Type Border}">
                <Setter Property="Background">
                    <Setter.Value>
                        <LinearGradientBrush StartPoint="0,1" EndPoint="1,0">
                            <GradientStop Color="#FF222222" Offset="0" />
                            <GradientStop Color="#FF222222" Offset="0.2" />
                            <GradientStop Color="#FFAAAAAA" Offset="0.6" />
                            <GradientStop Color="#FF222222" Offset="0.7" />
                            <GradientStop Color="#FFAAAAAA" Offset="0.9" />
                            <GradientStop Color="#FF222222" Offset="1" />
                        </LinearGradientBrush>
                    </Setter.Value>
                </Setter>
            </Style>

            <Style x:Key="WindowHeaderedContent" TargetType="{x:Type HeaderedContentControl}">
                <Setter Property="HeaderTemplate">
                    <Setter.Value>
                        <DataTemplate>
                            <Border 
                                Background="Black"
                                BorderBrush="Black" 
                                BorderThickness="1"
                                CornerRadius="5,5,0,0"
                                Padding="4"
                                SnapsToDevicePixels="True"
                                >
                                <DockPanel>
                                    <Button DockPanel.Dock="Right" Command="{Binding Path=CloseCommand}">X</Button>
                                    <TextBlock
                                        FontSize="14"
                                        FontWeight="Bold"
                                        Foreground="White"
                                        HorizontalAlignment="Center"
                                        Text="{TemplateBinding Content}" />
                                </DockPanel>
                            </Border>
                        </DataTemplate>
                    </Setter.Value>
                </Setter>
            </Style>
        </ResourceDictionary>
    </Window.Resources>

    <Border CornerRadius="5" Style="{StaticResource WindowBorderBackground}">
        <HeaderedContentControl Header="Current Contexts" 
                                Style="{StaticResource WindowHeaderedContent}" 
                                >
        </HeaderedContentControl>
    </Border>
</Window>

基本上,绘制一个具有漂亮渐变背景的窗口,使用HeaderedContentControl创建标题栏,标题栏使用HeaderTemplate将x按钮放在那里。

像这样:

但是,正如您所看到的,我已经尝试将X(close)按钮的命令绑定到ViewModel中的close命令。假设我的ViewModel是正确的,并且我对WPF数据绑定的理解不足是问题所在,那么我做错了什么?不能用我现在的方式来做吗?

(注意:出于这个问题的目的,我将窗口使用的所有资源合并到windows资源字典中。)

因为Sam建议我的窗口的DataContext没有设置,所以我将澄清它是设置的,但是在App.Xaml创建主窗口时在代码隐藏中完成。

/// <summary>
/// Interaction logic for App.xaml
/// </summary>
public partial class App : Application
{
    protected override void OnStartup(StartupEventArgs e)
    {
        base.OnStartup(e);

        MainWindow mainWindow = new MainWindow();            
        var viewModel = new MainWindowViewModel();

        viewModel.RequestClose += (s, ev) => mainWindow.Close();

        mainWindow.DataContext = viewModel;

        mainWindow.Show();
    }
}