TwoWay绑定一个ComboBox到一个静态属性

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因此，我认为以及来自所有答案的代码段。感谢那。我的问题是，我的dev-maschine运行.NET4.5，行为不同！同样的程序（针对.NET4.0编译）在.NET4.0的机器上正确运行，但在.NET4.5的机器上运行不正确。

So, i figured that my code is correct and so are the code snippets from all of your answers. Thanks for that. My problem is that my dev-maschine runs .NET4.5 which behaves differently! The very same program (compiled against .NET4.0) runs correct on a maschine with .NET4.0 but not on a maschine with .NET4.5!

是我修订的问题。

So here is my revised question.

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首先，简单的例子如何双向绑定我的组合框到我的数据上下文：

First, the simple example how i two-way bind my combobox to my data context:

查看模型：

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

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

和代码隐藏

private readonly MainWindowViewModel _viewModel = new MainWindowViewModel();
public MainWindow()
{
    InitializeComponent();
    DataContext = _viewModel;
}

和我的xaml

<ComboBox
        ItemsSource="{Binding MyElements, Mode=OneWay}"
        SelectedItem="{Binding SelectedElement}" />

这很好，如果我选择一个项目组合框，它绑定到我的视图模型。

This works fine and if i select an item whith the combobox, it is bound to my view model.

确定，现在我想让我的viewModel静态，但仍然双向绑定selectedItem。我试试这个：

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";
    }
}

我不需要在代码中设置datacontext -behind，我知道，xaml需要一个双向绑定的实例，所以我仍然有默认的构造函数。然后我绑定组合框

I do not need to set the datacontext in the Code-behind anymore and i know, that xaml needs an instance for two-way binding, so i have still the default constructor. I then bind the combobox

<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>

初始值已正确绑定，但如果我选择另一个项目与组合框，它不会反映我的viewModel。我做错了什么？

The initial value is properly bound, but if i select another item with the combobox it it not reflected in my viewModel. What am i doing wrong?

编辑：

同一个绑定字符串为一个TextBox并改变框中的文本，它就反映在属性中。

If I use the exact same binding string for a TextBox and change the text in the box, it is reflected in the property.

<TextBox Text="{Binding Source={StaticResource model}, Path=SelectedElement}"/>

显然我的绑定字符串是正确的，但是我使用combobox的方式似乎是错误的。我也试图绑定 SelectedValue 而不是...也没有改变。

So obviously my binding string is correct but the way i use the combobox seems to be wrong. I also tried to bind SelectedValue instead... no change either.