使用 MVVM 时，C# WPF 一个控件中有两个不同的 DataContext，并且第二个属性每次都是相同的

发布于 2024-11-06 05:18:51 字数 1491 浏览 0 评论 0原文

首先是代码：

<ListView ItemsSource="{Binding DataTransferModel.Output}" Background="Transparent" Margin="0" VerticalContentAlignment="Top" AlternationCount="2" Name="lvOutput" ScrollViewer.VerticalScrollBarVisibility="Auto" Grid.Row="2">
    <ListView.ItemTemplate>
        <DataTemplate>
            <StackPanel Orientation="Horizontal" Margin="0,1">
                <UserControls:OutputTextBox Text="{Binding Data, Mode=OneWay}" 
                                            IsReadOnly="True" 
                                            Grid.Row="2" 
                                            TextWrapping="WrapWithOverflow" 
                                            SelectedValue="{Binding Path=DataContext.SelectedOutput, 
                                                            Mode=TwoWay, 
                                                            UpdateSourceTrigger=PropertyChanged, 
                                                            RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Grid}}
                                                            }" 
                                            />
            </StackPanel>
        </DataTemplate>
    </ListView.ItemTemplate>
</ListView>

问题是OutputTextBox 控件上的属性Data 来自列表，但属性SelectedOutput 应该来自ViewModel 的主DataContext。对于列表中的每个条目，属性 SelectedOutput 应该相同。但目前还行不通。 :(

原文

First the code:

<ListView ItemsSource="{Binding DataTransferModel.Output}" Background="Transparent" Margin="0" VerticalContentAlignment="Top" AlternationCount="2" Name="lvOutput" ScrollViewer.VerticalScrollBarVisibility="Auto" Grid.Row="2">
    <ListView.ItemTemplate>
        <DataTemplate>
            <StackPanel Orientation="Horizontal" Margin="0,1">
                <UserControls:OutputTextBox Text="{Binding Data, Mode=OneWay}" 
                                            IsReadOnly="True" 
                                            Grid.Row="2" 
                                            TextWrapping="WrapWithOverflow" 
                                            SelectedValue="{Binding Path=DataContext.SelectedOutput, 
                                                            Mode=TwoWay, 
                                                            UpdateSourceTrigger=PropertyChanged, 
                                                            RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Grid}}
                                                            }" 
                                            />
            </StackPanel>
        </DataTemplate>
    </ListView.ItemTemplate>
</ListView>

And the problem is that the property Data on the OutputTextBox control comes from the list, but the property SelectedOutput should come from the main DataContext the ViewModel. And the property SelectedOutput should be the same for every entry in the list. But currently it dosn't work. :(

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雄赳赳气昂昂 2024-11-13 05:18:51

您的列表视图是否包含在标签中，如果是，网格是否具有来自 ViewModel 的 DataContext？如果是，它应该有效。

您在输出窗口中看到任何绑定错误吗？也许您应该尝试使用 Snoop 来查看 SelectedValue 的真实绑定。

编辑：请尝试除网格之外的类型，如果具有 ViewModel DataContext，则可能是 ListView。

<UserControls:OutputTextBox Text="{Binding Data, Mode=OneWay}" 
                                        IsReadOnly="True" 
                                        Grid.Row="2" 
                                        TextWrapping="WrapWithOverflow" 
                                        SelectedValue="{Binding Path=DataContext.SelectedOutput, 
                                                        Mode=TwoWay, 
                                                        UpdateSourceTrigger=PropertyChanged, 
                                                        RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListView}}
                                                        }" 
                                        />

does your listview is enclosed in tags and if yes does the grid has the DataContext from the ViewModel? if yes it should work.

do you see any binding errors in your output window? maybe you should try using Snoop to see your real binding of SelectedValue.

EDIT: Please try a Type other then Grid, maybe ListView if it has the ViewModel DataContext.

<UserControls:OutputTextBox Text="{Binding Data, Mode=OneWay}" 
                                        IsReadOnly="True" 
                                        Grid.Row="2" 
                                        TextWrapping="WrapWithOverflow" 
                                        SelectedValue="{Binding Path=DataContext.SelectedOutput, 
                                                        Mode=TwoWay, 
                                                        UpdateSourceTrigger=PropertyChanged, 
                                                        RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListView}}
                                                        }" 
                                        />

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