WPF MVVM处理数据网格单元更改

Question

我试图赶上CellEditEnding事件并获取行+列号和新值到我的视图模型。

我尝试使用MVVM如何处理数据网格单元更改？ 但我得到这个例外

“找不到类型'GalaSoft_MvvmLight_Command'。请验证您没有缺少程序集引用，并且所有引用程序集均已构建”。 我已经引用了GalaSoft.MvvmLight.WPF4.dll。

这是我的dataGrid：

 <DataGrid MaxHeight="600" AutoGenerateColumns="False" VerticalScrollBarVisibility="Auto"
                  ItemsSource="{Binding BitTestParam,Mode=TwoWay}" GridLinesVisibility="None" RowBackground="{x:Null}" Background="{x:Null}"
                  BorderThickness="2" BorderBrush="Black" HeadersVisibility="Column" Foreground="Black" FontStyle="Italic" FontWeight="SemiBold">
            <i:Interaction.Triggers>
                <i:EventTrigger EventName="CellEditEnding">
                    <i:InvokeCommandAction Command="{Binding CellChangedCommand}" CommandParameter="{Binding}"/>
                    <!--<GalaSoft_MvvmLight_Command:EventToCommand PassEventArgsToCommand="True" Command="{Binding CellEditEndingCommand}"/>-->
                </i:EventTrigger>
            </i:Interaction.Triggers>
            <DataGrid.Columns>
                <DataGridTextColumn Header="Input Param" Binding="{Binding InputNames}"/>
                <DataGridTextColumn x:Name="InputValuesColumn" Header="Param value" Binding="{Binding InputValues}" />
                <DataGridTextColumn Header="Output Param" Binding="{Binding OutputNames}"/>
                <DataGridTextColumn Header="Measure value" Binding="{Binding OutputValues}"/>
                <DataGridTextColumn Header="Error Messages" Binding="{Binding ErrorMessages}"/>
                <DataGridTextColumn Header="Warning Messages" Binding="{Binding WarningMessages}" />
            </DataGrid.Columns>
        </DataGrid>

这是我在viewModel中的相关代码：

public RelayCommand<object> CellChangedCommand
{
    get;
    set;
}

CellChangedCommand = new RelayCommand<object>(CellChangedEvent);

void CellChangedEvent(object obj)
{

}

我得到带有参数的命令“ CellChangedCommand”，但我需要获取行+列号和新值。

谢谢

Answer 1

我将让用户在单独的面板中进行编辑，并在那里进行处理程序验证。 该示例就是这样工作的： https : //gallery.technet.microsoft.com/scriptcenter/WPF-Entity-Framework-MVVM-78cdc204

在那您将找到一些代码，这些代码可以算出哪个绑定只是将数据从视图传输到视图模型。 即使用户在数据网格中进行编辑，您仍然可以使用它。 您只需要在数据网格周围放置一个网格或面板即可。 它甚至可以在数据网格中工作，我必须尝试确定一下。 但是，如果您查看该项目的资源字典，将会看到：

    <Grid Visibility="{Binding IsInEditMode, Converter={StaticResource BooleanToVisibilityConverter}}" 
           Width="{Binding ElementName=dg, Path=ActualWidth}"
           Height="{Binding ElementName=dg, Path=ActualHeight}"
           >
                <i:Interaction.Triggers>
                    <local:RoutedEventTrigger RoutedEvent="{x:Static Validation.ErrorEvent}">
                        <e2c:EventToCommand
                                                Command="{Binding EditVM.TheEntity.ConversionErrorCommand, Mode=OneWay}"
                                                EventArgsConverter="{StaticResource BindingErrorEventArgsConverter}"
                                                PassEventArgsToCommand="True" />
                    </local:RoutedEventTrigger>
                    <local:RoutedEventTrigger RoutedEvent="{x:Static Binding.SourceUpdatedEvent}">
                        <e2c:EventToCommand
                                                Command="{Binding EditVM.TheEntity.SourceUpdatedCommand, Mode=OneWay}"
                                                EventArgsConverter="{StaticResource BindingSourcePropertyConverter}"
                                                PassEventArgsToCommand="True" />
                    </local:RoutedEventTrigger>
                </i:Interaction.Triggers>

转换失败或删除失败由前者抓住，而数据传输则由后者抓住。

您需要标记到notifyonsourceupdated的绑定-一个示例绑定是：

<TextBox Text="{Binding  EditVM.TheEntity.Address1, 
                        UpdateSourceTrigger=PropertyChanged, 
                        NotifyOnSourceUpdated=True,
                        NotifyOnValidationError=True,
                        Mode=TwoWay}"  />

如果我错过了一些其他代码在示例中。 路由事件触发

public class RoutedEventTrigger : EventTriggerBase<DependencyObject>
{
    RoutedEvent routedEvent;
    public RoutedEvent RoutedEvent
    {
        get
        {
            return routedEvent;
        }
        set 
        { 
            routedEvent = value;
        }
    }

    public RoutedEventTrigger()
    {
    }
    protected override void OnAttached()
    {
        Behavior behavior = base.AssociatedObject as Behavior;
        FrameworkElement associatedElement = base.AssociatedObject as FrameworkElement;
        if (behavior != null)
        {
            associatedElement = ((IAttachedObject)behavior).AssociatedObject as FrameworkElement;
        } 
        if (associatedElement == null)
        {
            throw new ArgumentException("This only works with framework elements");
        }
        if (RoutedEvent != null)
        {
            associatedElement.AddHandler(RoutedEvent, new RoutedEventHandler(this.OnRoutedEvent));
        }
    }
    void OnRoutedEvent(object sender, RoutedEventArgs args)
    {
         base.OnEvent(args);
    }
    protected override string GetEventName()
    {
        return RoutedEvent.Name;
    }
}

绑定源属性转换器

public class BindingSourcePropertyConverter: IEventArgsConverter
{
    public object Convert(object value, object parameter)
    {
        DataTransferEventArgs e = (DataTransferEventArgs)value;
        BindingExpression binding = ((FrameworkElement)e.TargetObject).GetBindingExpression(e.Property);
        return binding.ResolvedSourcePropertyName ?? "";
    }
}