使用ItemSource时ComboboxItem的WPF绑定错误

Question

我有一个WPF应用程序（.Net 4.5.1），可以在组合框中动态创建项目，并使用可观察的集合绑定到ItemSource。 但是，当我这样做时，对于我添加的每个项目，我都会遇到两个绑定错误，一个是VeticalContentAlignment，一个是Horizo​​ntalContentAlignment。

System.Windows.Data Error: 4 : 
Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='System.Windows.Controls.ItemsControl', AncestorLevel='1''. 
BindingExpression:Path=VerticalContentAlignment; DataItem=null; target element is 'ComboBoxItem' (Name='PhoneItem'); 
target property is 'VerticalContentAlignment' (type 'VerticalAlignment')

我用Google搜索，发现了一些三分球没有帮助 ，如添加全局样式

<Style TargetType="{x:Type ComboBoxItem}">
    <Setter Property="HorizontalContentAlignment" Value="Stretch" />
    <Setter Property="VerticalContentAlignment" Value="Center" />
 </Style>

或在组合框中定义嵌入式容器样式。

<ComboBox.ItemContainerStyle>
    <Style TargetType="ComboBoxItem">
       <Setter Property="HorizontalContentAlignment" Value="Left" />
       <Setter Property="VerticalContentAlignment" Value="Center" />
    </Style>
</ComboBox.ItemContainerStyle>

我可以在一个干净的项目中重现此代码，该项目没有样式，只有组合框绑定到可观察的集合，如果有人对我的剥离代码感兴趣的话。

更新1-我的XAML和背后的代码

<Window x:Class="WpfApplicationDynamicComboBox.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <StackPanel>

            <Button Click="ButtonBase_OnClick" Margin="5">Load Combobox</Button>

            <ComboBox Name="DynamicComboBox"
                      ItemsSource="{Binding MyItems}"
                      Width="400"/>

        </StackPanel>
    </Grid>
</Window>


public partial class MainWindow : Window
{
  public MainWindow()
  {
    InitializeComponent();

    DataContext = this;
    MyItems = new ObservableCollection<ComboBoxItem>();
    MyItems.Add( new ComboBoxItem {Content = string.Format( "Phone: {0}", "123" ), Name = "PhoneItem_" + DateTime.Now.Second} );
  }

  public ObservableCollection<ComboBoxItem> MyItems { get; set; }

  private void ButtonBase_OnClick( object sender, RoutedEventArgs e )
  {
    MyItems.Add( new ComboBoxItem {Content = string.Format( "Phone: {0}", "123" ), Name = "PhoneItem_" + DateTime.Now.Second} );
  }
}

更新2-链接到示例项目 http://bit.ly/1fwvgkZ

摆脱这些错误的任何帮助将不胜感激！

Answer 1

好的，可以解决您的错误。 只需将您的代码替换为

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        DataContext = this;

        MyItems = new ObservableCollection<ComboBoxItem>();
        MyItems.Add(new ComboBoxItem
        {
            Name = "PhoneItem_" + DateTime.Now.Second,
            Content = string.Format("Phone: {0}", "123"),
            HorizontalContentAlignment = HorizontalAlignment.Left,
            VerticalContentAlignment = VerticalAlignment.Center
        });
    }


    public ObservableCollection<ComboBoxItem> MyItems { get; set; }

    private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
    {
        MyItems.Add(new ComboBoxItem
        {
            Name = "PhoneItem_" + DateTime.Now.Second,
            Content = string.Format("Phone: {0}", "123"),
            HorizontalContentAlignment = HorizontalAlignment.Left,
            VerticalContentAlignment = VerticalAlignment.Center
        });
    }


}