C# 如果内容与其他属性值匹配，则更改标签前景

我有一个DataGrid，它显示了一个包含一些细节的地图列表。我正在尝试更改当前处于活动状态的地图的前景色，但我正在努力。我编写了以下转换器来检查DataGrid项的值是否与当前映射的名称匹配，但我不确定如何从XAML传递当前映射的名称

转换器：

public class StringToBrushConverter : IValueConverter
{
    public string CurrentMapName { get; set; }
    public Color CurrentMapColor { get; set; }
    public Color OtherMapColor { get; set; }

    string _value = "";

    public StringToBrushConverter(string currentMapName, Color currentMapColor, Color otherMapColor)
    {
        CurrentMapName = currentMapName;
        CurrentMapColor = currentMapColor;
        OtherMapColor = otherMapColor;
    }

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        _value = value as string;
        return (string)value == CurrentMapName ? new SolidColorBrush(CurrentMapColor) : new SolidColorBrush(OtherMapColor);
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return _value; //TODO: Will this work?
    }
}

public sealed class RaceMapColorConverter : StringToBrushConverter
{
    public RaceMapColorConverter() : base("", new Color { R = 255, G = 0, B = 0 }, new Color { R = 255, G = 255, B = 255 }) { }
}

<DataGrid x:Name="MapHistory"
        AutoGenerateColumns="False"
        IsReadOnly="True"
        HeadersVisibility="Column"
        GridLinesVisibility="None"
        CanUserSortColumns="False"
        Style="{StaticResource MapTimerDataGrid}"
        CellStyle="{StaticResource MapTimerControlCell}"
        ItemsSource="{Binding Plan.Plan}">
    <DataGrid.Resources>
<!-- The Binding in CurrentMapName is not valid. It says it can only be set on a dependency property but I'm not sure how to do that -->
        <conv:RaceMapColorConverter x:Key="MapColorConverter" CurrentMapName="{Binding CurrentMap.MapName}" CurrentMapColor="Red" OtherMapColor="White" />
    </DataGrid.Resources>
    <DataGrid.Columns>
        <DataGridTemplateColumn Header="Map" Width="*">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <Label Content="{Binding Map.MapName}" Foreground="{Binding Map.MapName, Converter={StaticResource MapColorConverter}}" Padding="0" />
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
        <!-- Other columns removed to shorten -->
    </DataGrid.Columns>
</DataGrid>

XAML:

public class StringToBrushConverter : IValueConverter
{
    public string CurrentMapName { get; set; }
    public Color CurrentMapColor { get; set; }
    public Color OtherMapColor { get; set; }

    string _value = "";

    public StringToBrushConverter(string currentMapName, Color currentMapColor, Color otherMapColor)
    {
        CurrentMapName = currentMapName;
        CurrentMapColor = currentMapColor;
        OtherMapColor = otherMapColor;
    }

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        _value = value as string;
        return (string)value == CurrentMapName ? new SolidColorBrush(CurrentMapColor) : new SolidColorBrush(OtherMapColor);
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return _value; //TODO: Will this work?
    }
}

public sealed class RaceMapColorConverter : StringToBrushConverter
{
    public RaceMapColorConverter() : base("", new Color { R = 255, G = 0, B = 0 }, new Color { R = 255, G = 255, B = 255 }) { }
}

<DataGrid x:Name="MapHistory"
        AutoGenerateColumns="False"
        IsReadOnly="True"
        HeadersVisibility="Column"
        GridLinesVisibility="None"
        CanUserSortColumns="False"
        Style="{StaticResource MapTimerDataGrid}"
        CellStyle="{StaticResource MapTimerControlCell}"
        ItemsSource="{Binding Plan.Plan}">
    <DataGrid.Resources>
<!-- The Binding in CurrentMapName is not valid. It says it can only be set on a dependency property but I'm not sure how to do that -->
        <conv:RaceMapColorConverter x:Key="MapColorConverter" CurrentMapName="{Binding CurrentMap.MapName}" CurrentMapColor="Red" OtherMapColor="White" />
    </DataGrid.Resources>
    <DataGrid.Columns>
        <DataGridTemplateColumn Header="Map" Width="*">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <Label Content="{Binding Map.MapName}" Foreground="{Binding Map.MapName, Converter={StaticResource MapColorConverter}}" Padding="0" />
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
        <!-- Other columns removed to shorten -->
    </DataGrid.Columns>
</DataGrid>

---

我也不知道如何实现“ConvertBack（）”。将原始值存储在转换器中是否有效？或者可以为同一控件创建新实例吗？我这样做对吗？我想值得一提的是，我正在使用Caliburn.Micro，以防它有任何可能有用的技巧。如果您需要任何帮助，我们将不胜感激。

一般经验法则是，当数据转换需要双向（即查看模型以查看并再次返回）时，您应该使用转换器；当数据转换需要单向时，您应该使用数据触发器。这就回答了您关于ConvertBack的问题（在您提供的示例中，无论如何都不会调用ConvertBack，在这种情况下，您可以返回Binding.DoNothing）

然而，在这种特殊情况下，转换器是有保证的，因为您需要比较两个绑定。与其为这项非常具体的任务编写一个应用程序感知转换器，不如选择一个更通用的多转换器，它只比较您提供的两个值：

public class EqualityConverter : IMultiValueConverter
{
    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        return (values.Length==2) && Object.Equals(values[0], values[1]);
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        return new object[] { Binding.DoNothing, Binding.DoNothing };
    }
}

然后回到应用程序中，将两个绑定传递到该类型的多重绑定中，并在比较结果为真时使用DataTrigger更改映射颜色：

<Label Content="{Binding Map.MapName}">
    <Label.Style>
        <Style TargetType="{x:Type TextBlock}" BasedOn="{StaticResource {x:Type Label}}">
            <Setter Property="Foreground" Value="Red" /> <!-- normal map color -->
            <Style.Triggers>
                <DataTrigger Value="True">
                    <DataTrigger.Binding>
                        <MultiBinding Converter="{StaticResource EqualityConverter}" Mode="OneWay">
                            <Binding Path="Map.MapName" />
                            <Binding Path="CurrentMapName" />
                        </MultiBinding>
                    </DataTrigger.Binding>
                    <Setter Property="Foreground" Value="White" /> <!-- other map color -->
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </Label.Style>
</Label>

---

您真的需要

ConvertBack

在这里将画笔转换为地图名称吗？方法告诉您在这种情况下使用

dependencProperty.UnsetValue

或

Binding.DoNothing