从内容控件访问标签元素并在数据模板中访问它 [英] Accesing the Tag Element from Content Control and access it inside the Data Template

问题描述

我有一个ContentControl，将其内容设置为DataTemplate.我正在设置ContentControl的Tag值.有没有一种方法可以访问数据模板中的此Tag元素并将其作为CommandParameter传递.换句话说，我正在尝试将Tag作为参数传递给DataTemplate.请帮忙.

I have a ContentControl where I am setting its content to a DataTemplate. I am setting the Tag value of the ContentControl. Is there a way to access this Tag Element in the Data Template and pass it as CommandParameter. In other words I am trying to pass the Tag as a parameter to the DataTemplate. Please help.

   <DataTemplate x:Key="SensorStatusControlTemplate" x:DataType="viewModel:SensorBufferState">
                <Grid>
                    <Rectangle x:Name="SensorRectangle"
                               Fill="{x:Bind Converter={StaticResource SensorStateOverflowConverter},
ConverterParameter={What do I say here to get the Tag}}"
                               Height="30"
                               Width="125" />
                    <TextBlock x:Name="SensorTextBlock"
                               Text="{x:Bind Converter={StaticResource SensorStateOverflowConverter}}"
                               FontSize="{StaticResource FontSizeMedium}"
                               HorizontalAlignment="Center"
                               VerticalAlignment="Center"
                               Foreground="White" />
                </Grid>
            </DataTemplate>

这是我的ControlTemplate.是否可以访问DataTemplate中的标签?

Here is my ControlTemplate. Is there a way to access the Tag in the DataTemplate?

<ContentControl Content="{Binding VmPRWControlData.OverflowSensorState,UpdateSourceTrigger=PropertyChanged}"
                                        ContentTemplate="{StaticResource SensorStatusControlTemplate}"
                                        Tag="Overflow"
                                        HorizontalAlignment="Center"
                                        Width="{Binding ElementName=LABLidSensorTextBlock,Path=ActualWidth}" />

我已经尝试过这样做，但是参数值为null，

I have tried doing like this but the parameter value is null,

ConverterParameter={Binding Tag, RelativeSource={RelativeSource Mode=TemplatedParent}}

推荐答案

您应该使用 RelativeSource.AncestorType 遍历树以找到父控件:

You should traverse the tree to find the parent control using RelativeSource.AncestorType:

<DataTemplate DataType="{x:Type viewModel:SensorBufferState}">
  <Button CommandParameter="{Binding RelativeSource={RelativeSource AncestorType=ContentControl}, Path=Tag}"/>
</DataTemplate>

---

正如您正确提到的那样，UWP不支持 RelativeSource.AncestorType .

以下解决方案也适用于WPF:

The following solutions work with WPF too:

您可以改用 Binding.ElementName

App.xaml

<DataTemplate x:Key="DataTemplate">
  <Button CommandParameter="{Binding ElementName=ContentControl, Path=Tag}"/>
</DataTemplate>

MainPage.xaml

<ContentControl x:Name="ContentControl" 
                Tag="123"  
                ContentTemplate="{StaticResource DataTemplate}" />

---

解决方案2

或者使用 DataContext 设置为视图模型或 DependencyProperty 代替 Tag 属性:

---

Solution 2

Or alternatively use the DataContext set to a view model or a DependencyProperty instead of the Tag property:

App.xaml

<DataTemplate x:Key="DataTemplate">
  <Button CommandParameter="{Binding CommandParameterValue}"/>
</DataTemplate>

MainPage.xaml.cs

public sealed partial class MainPage : Page
{
  public static readonly DependencyProperty CommandParameterValueProperty = DependencyProperty.Register(
    "CommandParameterValue",
    typeof(string),
    typeof(MainPage),
    new PropertyMetadata(default(string)));

  public string CommandParameterValue 
  { 
    get => (string) GetValue(MainPage.CommandParameterValueProperty); 
    set => SetValue(MainPage.CommandParameterValueProperty, value); 
  }

  public MainPage()
  {
    this.InitializeComponent();
    this.DataContext = this;
    this.CommandParameterValue = "ABC";
  }
}

MainPage.xaml

<ContentControl ContentTemplate="{StaticResource DataTemplate}" />

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