c# - WPF MVVM 带参数的数据绑定(bind)？

Question

所以我之前的问题似乎无法回答，所以我将根据自己的建议尝试一下。

我正在寻找的功能是，当单元格中的数据已被编辑时，让数据网格更改该单元格的前景(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;
        }
    }
}

我显然已经删除了大部分属性，而现在的 HasChanged 纯粹是神话，但我希望的是，我可以以某种方式将 DataGridTextColumn 前景(或希望背景)绑定(bind)到此 HasChanged 方法，并以某种方式传递当前正在调用该方法的参数。

<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(bind)识别哪个属性发生了变化，这与 IDataErrorInfo 允许对每个属性绑定(bind)验证的方式非常相似。虽然我不知道它在后台实际如何运作。

Answer 1

它需要一个转换器，不是吗？所以你的绑定(bind)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有效。如果做不到这一点，您可以使用扩展格式进行绑定(bind):

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

更新二:...显然我们不能绕过更改 DataGridTextColumn 的背景，因此请将列的 XAML 更改为如下内容:

<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>