WPF的SelectedItem与DataTemplate的可编辑组合框的问题 [英] Problem with SelectedItem of WPF Editable ComboBox with DataTemplate

问题描述

我在WPF ComboBox 遇到以下问题：

I’m having the following issue with WPF ComboBox:

<Window.Resources>
  <ResourceDictionary>
    <DataTemplate DataType="{x:Type this:Data}">

      <ComboBox IsTextSearchEnabled="False" IsEditable="True" 
                Text="{Binding Value}" ItemsSource="{Binding Menu}"/>

    </DataTemplate>
  </ResourceDictionary>
</Window.Resources>

<StackPanel>
  <ContentControl Content="{Binding}"/>
  <Button Click="ChangeData_Click">Change Data</Button>
</StackPanel>

代码：

Code behind:

public Window1()
{
    InitializeComponent();
    DataContext = new Data();
}

void ChangeData_Click(object sender, RoutedEventArgs e)
{
    DataContext = new Data();
}

我打开窗口并获取 ComboBox

I open the window and get ComboBox, bounded to my data model, I select some item (e.g. 1), all is dandy.

我将数据上下文更改为一个新的数据模型 - 我选择了一个项目（例如1），所有都是dandy。所选项目是（令我惊讶的）1 ...我不期望任何选定的项目...

I change the data context to a new data model – the selected item is (to my surprise) 1... Where I don't expect any selected item...

我怀疑它与组合有关

我发现一个工作：调用 UpdateLayout（）

I found a work around: call UpdateLayout() on the ContentControl bounded to the DataContext, but it’s ugly.

是WPF错误吗？这是我的错吗？

Is that WPF bug? Is it all my fault?

请帮助

推荐答案

我们向提交了相同的问题MSDN WPF论坛，它似乎是一个微软的错误。
有一个解决方法，我发现，丑陋，但它的工作。这是修改后的代码：

I've submitted the same question to MSDN WPF Forum and it seems like a Microsoft bug. There's a workaround I found, ugly, but it's working. Here's the modified code behind:

    public Window1()
    {
        InitializeComponent();
        DataContext = new Data();
        DataContextChanged += delegate { contentControl.UpdateLayout(); };
    }

    void ChangeData_Click(object sender, RoutedEventArgs e)
    {
        DataContext = null;
        DataContext = new Data();
    }

$ b需要解决这个问题。

Note that both setting the DataContext to null and calling UpdateLayout() on DataContextChanged are needed to solve this issue.

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