在 WPF 中使用 MVVM 从其他绑定更新绑定

Question

有人对如何解决我的问题有任何建议吗？我有一个绑定到ModelCheckoutRecord 对象（ListModelCheckoutRecords）的集合的数据网格。我将所选项目绑定到ModelCheckoutRecord (SelectedItemModelCheckoutRecord)。在所选项目的绑定中，我想更新另一个数据网格和网格拆分器 (ResponseVisibility) 的可见性绑定。从其他绑定更新绑定的功能似乎不起作用？

我的 XAML 行如下：

            <Grid>
                <Grid.RowDefinitions>
                    <View:RowDefinitionExtended Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                </Grid.RowDefinitions>
                <DataGrid AutoGenerateColumns="True" ItemsSource="{Binding ListModelCheckoutRecord}" SelectedItem="{Binding SelectedModelCheckoutRecord}" MouseLeftButtonDown="DataGrid_MouseLeftButtonDown" CommandManager.PreviewExecuted="DataGrid_DeletePreviewExecuted" IsReadOnly="False" CanUserAddRows="False" CanUserDeleteRows="True" Margin="15" Grid.Row="0"/>
                <GridSplitter HorizontalAlignment="Stretch" Visibility="{Binding ResponseVisibility}" Grid.Row="1"/>
                <DataGrid AutoGenerateColumns="True" ItemsSource="{Binding ListModelResponseRecord}" SelectedItem="{Binding SelectedModelResponseRecord}" MouseLeftButtonDown="DataGrid_MouseLeftButtonDown" IsReadOnly="False" CanUserAddRows="False" CanUserDeleteRows="False" Visibility="{Binding ResponseVisibility}" Margin="15" Grid.Row="2"/>
            </Grid>

给我带来麻烦的精简代码如下：

    private Visibility responseVisibility = Visibility.Visible;
    public Visibility ResponseVisibility
    {
        get { return responseVisibility; }
        set
        {
            if (value == responseVisibility)
            {
                return;
            }

            responseVisibility = value;
            RaisePropertyChanged("ResponseVisibility");
        }
    }

    private List<ModelCheckoutRecord> listModelCheckoutRecord;
    public List<ModelCheckoutRecord> ListModelCheckoutRecord
    {
        get { return listModelCheckoutRecord; }
        set
        {
            if (value == listModelCheckoutRecord)
            {
                return;
            }

            listModelCheckoutRecord = value;
            RaisePropertyChanged("ListModelCheckoutRecord");

            ResponseVisibility = Visibility.Collapsed;
        }
    }

    private ModelCheckoutRecord selectedModelCheckoutRecord;
    public ModelCheckoutRecord SelectedModelCheckoutRecord
    {
        get { return selectedModelCheckoutRecord; }
        set
        {
            if (value == null)
            {
                ResponseVisibility = Visibility.Collapsed;
                return;
            }

            else
            {
                ResponseVisibility = Visibility.Visible;
            }

            if (selectedModelCheckoutRecord == value)
            {
                return;
            }

            RaisePropertyChanged("SelectedModelCheckoutRecord");
        }
    }

谢谢

理查德

Answer 1

假设您真的希望仅在 null SelectedItem 的情况下具有折叠可见性，则实际上无需为此使用代码。以下 XAML 可以很好地完成这项工作。

只需为您的源 DataGrid 命名（我在下面的示例中假设 Grid 作为名称）并在目标 DataGrid 中使用如下样式：

<DataGrid x:Name="TargetGridJustToShowWhereThisGoes">
    <DataGrid.Style>
        <Style TargetType="DataGrid">
            <Style.Triggers>
                <DataTrigger Binding="{Binding ElementName=Grid, Path=SelectedItem}" Value="{x:Null}">
                    <Setter Property="Visibility" Value="Collapsed" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </DataGrid.Style>
</DataGrid>