带参数的 WPF MVVM 数据绑定？

Question

所以我之前的问题似乎无法回答，所以我打算用我自己的建议来试一试。

我正在寻找的功能是，当单元格中的数据已被编辑时，数据网格会更改单元格的前景（甚至背景）。

我的模型看起来像这样：

Public class Shipment : PropertyChangedBase
{
    #region Fields
    private ShippingService.Shipment.lbnshipment _localShipment;
    private ShippingService.Shipment.lbnshipment _originalShipment;
    #endregion

    #region Properties
    public int ShipmentID
    {
        get { return _localShipment.ShipmentID; }
        set
        {
            if(value != _localShipment.ShipmentID)
            {
                _localShipment.ShipmentID = value;
                NotifyOfPropertyChange(() => ShipmentID);
            }
         }
    } 

    public Shipment(ShippingServices.Shipment.lbnShipment localshipment)
    {
        _originalShipment = localshipment;
        _localShipment = localshipment;
    }

    //This Section is my best guess solution, but it just a guess
    public Color HasChanged(string Property)
    {
        switch(Property)
        {
           case "ShipmentID":
               if(_localShipment.ShipmentID != _originalShipment.ShipmentID)
               {
                  return Colors.Red;
               } else {
                  return Colors.Black;
               }
               break;
        }
    }
}

我显然已经去掉了大部分属性，现在 HasChanged 是纯粹的神话，但我希望以某种方式，我可以将 DataGridTextColumn 前景（或希望背景）绑定到这个 HasChanged 方法，并以某种方式通过它是哪个参数当前正在调用该方法。

<DataGridTextColumn Header="ShipmentID" Binding="{Binding ShipmentID}" Foreground="{Binding HasChanged}" />

我希望有一些聪明的方法可以让绑定识别哪个属性发生了变化，这与 IDataErrorInfo 允许为每个属性绑定验证的方式非常相似。虽然我不知道它在后台的实际运作方式。

Answer 1

它需要转换器，不是吗？所以你的绑定看起来像这样：

<DataGridTextColumn.Foreground>
    <SolidColorBrush Color="{Binding Converter={StaticResource hasChangedConverter}, ConverterParameter='ShipmentID'}"/>
</DataGridTextColumn.Foreground>

你的转换器看起来像（剥离无关代码）：

class HasChangedConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        var shipment = value as Shipment;
        var property = parameter as string;

        return shipment.HasChanged(property);
    }
}

更新：如上所示在转换器参数上使用单引号应该可以工作。如果失败，您可以使用扩展格式进行绑定：

<SolidColorBrush.Color>
    <Binding Converter="{StaticResource hasChangedConverter}" ConverterParameter="ShipmentID"/>
</SolidColorBrush.Color>

更新二：...显然我们不能改变DataGridTextColumns的背景，所以将您的列的 XAML 更改为如下所示：

<DataGridTemplateColumn Header="ShipmentID">
    <DataGridTemplateColumn.CellTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding ShipmentID}">
                <TextBlock.Background> 
                    <SolidColorBrush Color="{Binding Path=ShipmentID, Converter={StaticResource HasChangedConv}}"/>
                </TextBlock.Background>
            </TextBlock>
        </DataTemplate>
    </DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>