Question

现在我搜索了2天为什么我的Binding不起作用。我在PopUp中有一个ListView。我想将SelectedItem绑定到Code-Behind。我之前做过1298736次，但在这种情况下它不起作用。

这是在点击时打开弹出窗口的按钮：

<Button  ToolTip="Emoticon einfügen" Name="SmileImg" Click="SmileImg_MouseLeftButtonDown">
    <Image   Source="..\Smileys\Smile.png" Stretch="None" SnapsToDevicePixels="True" ></Image>
</Button>

这是Popup定义

<Popup AllowsTransparency="True" Name="SmiliesPopup" PopupAnimation="Fade" Placement="Top" PlacementTarget="{Binding ElementName=SmileImg}" StaysOpen="False" >
    <ListView IsSynchronizedWithCurrentItem="true" BorderThickness="0" Name="EmoList" SelectedItem="{Binding SelectedSmile, Mode=TwoWay, ElementName=FsRichTextBoxControl}" SelectionMode="Single" ItemsSource="{Binding Emoticons, ElementName=FsRichTextBoxControl}">

        <ListView.ItemsPanel>
            <ItemsPanelTemplate>
                <WrapPanel MaxWidth="50" Orientation="Horizontal"></WrapPanel>
            </ItemsPanelTemplate>
        </ListView.ItemsPanel>
        <ListView.ItemTemplate>
            <DataTemplate>
                <Image Width="16" Margin="2" Source="{Binding Uri}"></Image>
            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>
</Popup>

所以这是代码：

public Emoticon SelectedSmile
{
  get { return m_selectedSmile; }
  set
  {
    if (m_selectedSmile == null)
    {
      m_selectedSmile = value;
    }
    else
    {
      if (value != null && EmoList.SelectedItem != null)
      {
        var emo = (Emoticon)EmoList.SelectedItem;
        InsertImage(new BitmapImage(emo.Uri));
        SmiliesPopup.IsOpen = false;
        EmoList.SelectedItem = null;
      }
      m_selectedSmile = value;
    }

    InvokePropertyChanged(new PropertyChangedEventArgs("SelectedSmile"));

  }
}

...

public RichtextBoxExt()
{
  Emoticons = new AsyncObservableCollection<Emoticon>
                {
                  new Emoticon("Smile", new Uri("pack://application:,,,/TeamNote;component/Smileys/Smile.png")),
                  new Emoticon("Cheeky", new Uri("pack://application:,,,/TeamNote;component/Smileys/Cheeky.png")),
                  new Emoticon("Cry", new Uri("pack://application:,,,/TeamNote;component/Smileys/Cry.png")),
                  new Emoticon("Kiss", new Uri("pack://application:,,,/TeamNote;component/Smileys/Kiss.png")),
                  new Emoticon("Wink", new Uri("pack://application:,,,/TeamNote;component/Smileys/Wink.png")),
                  new Emoticon("Sad", new Uri("pack://application:,,,/TeamNote;component/Smileys/Sad.png")),
                  new Emoticon("Laugh", new Uri("pack://application:,,,/TeamNote;component/Smileys/Laugh.png"))
                };
  SelectedSmile = new Emoticon("Smile", new Uri("pack://application:,,,/TeamNote;component/Smileys/Smile.png"));
  InitializeComponent();
  Initialize();

......等等。

ItemsSource Binding效果很好。 Online SelectedItem不起作用。 SelectionChanged事件也没有解雇。

PS：这只是一个原型，所以请专注于问题而不是编程风格：P

感谢您的帮助

UPDATE / Solution / Fixed ...无论如何：P

感谢您的所有答案。我找到了选择根本没有变化的原因......

private void RichtextBoxExt_GotFocus(object sender, RoutedEventArgs e)
{
  //TextBox.Focus();
  Debug.WriteLine("RichtextBoxExt_GotFocus");
}

CodeBehind中的这个事件处理程序每次点击一个项目时都会改变焦点，因此SelectedItem永远不会改变。

感谢您的想法！

Answer 1

模式= OneWay OneWay updates the target property only when the source property changes.

  <ListView IsSynchronizedWithCurrentItem="true" BorderThickness="0" Name="EmoList" SelectedItem="{Binding SelectedSmile, Mode=OneWay, ElementName=FsRichTextBoxControl}" SelectionMode="Single" ItemsSource="{Binding Emoticons, ElementName=FsRichTextBoxControl}" IsEnabled="False">

使用Mode = TwoWay。

Answer 2

如果您的SelectedSmile绑定为Mode=OneWay，您的视图（模型）将不会在更改时更新。

Answer 3

<ListView IsSynchronizedWithCurrentItem="true" BorderThickness="0" Name="EmoList" SelectedItem="{Binding DataContext.SelectedSmile, Mode=TwoWay, ElementName=FsRichTextBoxControl}" SelectionMode="Single" ItemsSource="{Binding Emoticons, ElementName=FsRichTextBoxControl}" IsEnabled="False">

我认为这就是错误所在：

SelectedItem="{Binding DataContext.SelectedSmile, Mode=TwoWay, ElementName=FsRichTextBoxControl}"

Answer 4

UPDATE / Solution / Fixed ...无论如何：P

感谢您的所有答案。我找到了选择根本没有变化的原因......

private void RichtextBoxExt_GotFocus(object sender, RoutedEventArgs e)
{
  //TextBox.Focus();
  Debug.WriteLine("RichtextBoxExt_GotFocus");
}

CodeBehind中的这个事件处理程序每次点击一个项目时都会改变焦点，因此SelectedItem永远不会改变。

感谢您的想法！

WPF ListView SelectedItem绑定问题

4 个答案: