从ResourceDictionary中绑定到祖先

Question

我如何UserControl从其内部绑定一个属性ResourceDictionary？我想要一个我在我的资源中声明的对象DataContext与UserControl它包含在的对象相同:

<UserControl
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:Some.Namespace"
    DataContext="{Binding Path=ViewModel, RelativeSource={RelativeSource Self}}">
    <UserControl.Resources>
        <local:SomeClass
            x:Key="SomeClass"
            DataContext="{Binding Path=DataContext, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}}" />
    </UserControl.Resources>
</UserControl>

在运行时我收到错误:

System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='UserControl', AncestorLevel='1''. BindingExpression:Path=DataContext; DataItem=null; target element is 'SomeClass' (Name=''); target property is 'DataContext' (type 'Object')

Answer 1

我的解决方法是DataContext在代码隐藏中设置资源的。

.xaml

<local:SomeType x:Key="SomeKey" SomeProperty="{Binding ... }" />

.xaml.cs

<local:SomeType x:Key="SomeKey" SomeProperty="{Binding ... }" />