我可以通过绑定到wpf父控件上的属性的依赖项属性在xaml中设置用户控件datacontext吗？

Question

I have a user control with a dependency property called ViewModel. I want the value that this property is set to to be the data context for this control.

Here is an example of its usage;

<uc:MyCustomControl ViewModel="{Binding CustomControlViewModel}"/>

Here is the code-behind for the ViewModel dependency property for "MyCustomControl"

    public static readonly DependencyProperty ViewModelProperty = DependencyProperty.Register(
        "ViewModel", typeof(CustomControlViewModel), typeof(MyCustomControl), new PropertyMetadata(default(CustomControlViewModel), PropertyChangedCallback));

    public CustomControlViewModel ViewModel
    {
        get { return (CustomControlViewModel)GetValue(ViewModelProperty); }
        set
        {
            SetValue(ViewModelProperty, value);
        }
    }

    private static void PropertyChangedCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
    {
        var control = (MyCustomControl) dependencyObject;
        if (control == null)
        {
            return;
        }
        control.DataContext = (CustomControlViewModel) dependencyPropertyChangedEventArgs.NewValue;
    }

This is the constructor for the "MyCustomControl";

    public MyCustomControl()
    {
        InitializeComponent();
    }

This doesn't seem to work, what might I be doing wrong?

Answer 1

DataContext itself is a DependencyProperty . You can directly assign it with your viewmodel like this.

<uc:MyCustomControl DataContext="{Binding CustomControlViewModel}"/>