Question

我在 DataTemplates.xaml

中有以下 DataTemplate

<DataTemplate DataType="{x:Type local:ExcelReportVM}">
    <local:ExcelReport DoubleClickHandler="{Binding}">
        <local:ExcelReport.RowColorConverter>
            <local:ReportRowColorConverter/>
        </local:ExcelReport.RowColorConverter>
    </local:ExcelReport>
</DataTemplate>

我通过以下 App.xaml 定义确保此DataTemplate在应用程序范围内可用：

<Application x:Class="WpfApplication1.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:local="clr-namespace:WpfApplication1"
             StartupUri="MainWindow.xaml">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="DataTemplates.xaml"/>
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>

这是我的控件 ExcelReport.xaml ：

<UserControl x:Class="WpfApplication1.ExcelReport"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              ....
             xmlns:syncfusion="http://schemas.syncfusion.com/wpf"
             d:DesignHeight="300" d:DesignWidth="300">
    <UserControl.Resources>
        <DataTemplate x:Key="HeaderTemplate">
            <TextBlock TextAlignment="Center" Text="{Binding .}" TextWrapping="WrapWithOverflow" />
        </DataTemplate>

    </UserControl.Resources>
    <UserControl.DataContext>
        <local:ExcelReportVM/>
    </UserControl.DataContext>
    <syncfusion:SfDataGrid ItemsSource="{Binding Entries}" x:Name="grid" Background="White"
                           HeaderTemplate="{StaticResource HeaderTemplate}"

                           SelectedItem="{Binding SelectedItem, RelativeSource={RelativeSource AncestorType=UserControl}}">
    </syncfusion:SfDataGrid>
</UserControl>

我的代码背后： ExcelReport.xaml.cs

   public partial class ExcelReport : UserControl
    {


  public static readonly DependencyProperty RowColorConverterProperty = DependencyProperty.Register(
              "RowColorConverter",
              typeof(IValueConverter),
              typeof(ExcelReport),
              new FrameworkPropertyMetadata(new PropertyChangedCallback(OnRowColorConverterChanged))
            );

    public IValueConverter RowColorConverter
        {
            get { return (IValueConverter)GetValue(RowColorConverterProperty); }
            set { SetValue(RowColorConverterProperty, value); }
        }

   public ExcelReport()
        {
            InitializeComponent();
            this.Loaded += OnLoaded;
        }

 private void OnLoaded(object sender, RoutedEventArgs e)
{  
    Debug.Assert(DataContext.GetType()==typeof(ExcelReportVM)); //DataContext is correct
    Debug.Assert(RowColorConverter!=null); //but this is null
  }
}

我不知道为什么我可以成功绑定DataContext，但我没有使用我定义的<DataTemplate DataType="{x:Type local:ExcelReportVM}">，我认为DataTemplates.xaml中的所有内容都可以通过ExcelReport.xaml访问？< / p>

注意：输出窗口中没有错误，并且代码中的任何位置都没有抛出任何异常。

Answer 1

如果是ContentControl，则必须将其Content设置为<ContentControl Content="{Binding SomeProperty}"/>，然后根据DataType SomeProperty更正DataTemplate被接走了。

Answer 2

这就是我解决问题的方法，我没有在UserControl.DataContext将ExcelReportVM设置为ExcelReport.xaml;相反，我将ContentControl.Content设置为ExcelReportVM MainWindow.xaml。

更新了 ExcelReport.xaml 的代码：

<UserControl x:Class="WpfApplication1.ExcelReport"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              ....
             xmlns:syncfusion="http://schemas.syncfusion.com/wpf"
             d:DesignHeight="300" d:DesignWidth="300">
    <UserControl.Resources>
        <DataTemplate x:Key="HeaderTemplate">
            <TextBlock TextAlignment="Center" Text="{Binding .}" TextWrapping="WrapWithOverflow" />
        </DataTemplate>

    </UserControl.Resources>
  <!--  <UserControl.DataContext>   this is not longer needed
        <local:ExcelReportVM/>
    </UserControl.DataContext> -->
    <syncfusion:SfDataGrid ItemsSource="{Binding Entries}" x:Name="grid" Background="White"
                           HeaderTemplate="{StaticResource HeaderTemplate}"

                           SelectedItem="{Binding SelectedItem, RelativeSource={RelativeSource AncestorType=UserControl}}">
    </syncfusion:SfDataGrid>
</UserControl>

MainWindow.xaml

的代码

<Syncfusion:RibbonWindow x:Class="WpfApplication1.MainWindow"
            ...
        xmlns:local="clr-namespace:WpfApplication1"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525" WindowState="Maximized"
        Syncfusion:SkinStorage.VisualStyle="Office2013"
        xmlns:Syncfusion="http://schemas.syncfusion.com/wpf">

    <Grid x:Name="ExcelReport22">
        <ContentControl>   <!-- this is where the ExcelReportVM is binded to -->
            <local:ExcelReportVM/>
        </ContentControl>

    </Grid>
</Syncfusion:RibbonWindow>

DataTemplate没有按指定的方式正确绑定属性

2 个答案: