TwoWay绑定ComboBox到.NET 4.5中的静态属性

好，我刚刚发布了这个问题，但我想我没有做错什么。我的代码（和所有答案的代码）是正确的，但我的dev-maschine运行与.NET4.5显然有一个问题绑定的组合框...

Well, i just posted this question, but i figured that i am not doing anything wrong. My code (and the code of all of the answers) is correct, but my dev-maschine runs with .NET4.5 which apparently has a problem with the binding of the combobox...

这里是一个新版本的问题：如何双向绑定组合框的SelectedItem到.NET4.5中的静态属性？

So here a new version of the question: How to two-way bind a combobox's SelectedItem to a static Property in .NET4.5?

以下代码片段在.net4中可用，但在.NET4.5中不可用。在4.5，只是选择的值不传播回我的静态属性。

The following code snippets work in .net4 but not in .NET4.5. In 4.5 it is just that the selected value is not propagated back into my static property.

我的ViewModel：

My ViewModel:

public class MainWindowViewModel
{
    public static List<String> MyElements { get; set; }
    public static string SelectedElement { get; set; }

    static MainWindowViewModel()
    {
        MyElements = new List<string>() {"a", "b", "c"};
        SelectedElement = "a";
    }
}

和我的XAML

<Window.Resources>
    <me:MainWindowViewModel x:Key="model"/>
</Window.Resources>

<StackPanel>
    <ComboBox
        ItemsSource="{Binding Source={x:Static me:MainWindowViewModel.MyElements}, Mode=OneWay}"
        SelectedItem="{Binding Source={StaticResource model}, Path=SelectedElement}" />
</StackPanel>

有人知道如何实现ComboBox的SelectedItem到静态属性的双向绑定在.NET4.5中？

Does anybody have an idea how to achieve this two-way binding of a ComboBox's SelectedItem to a static Property in .NET4.5?