Question

我需要WPF下的Style，在多个条件满了时设置几个属性。但是，我的一个条件是Not Equal To类型。我应该如何更改以下Style以使条件成为Not Equal To？是否可以在没有IValueConverter的情况下实现？

<Style>
    <Style.Triggers>
        <MultiDataTrigger>
             <MultiDataTrigger.Conditions>
                  <!--<Condition 1 here.../>-->
                  <!--<Condition 2 here.../>-->
                  <Condition Binding="{Binding Path=id}" Value="3"/>
             </MultiDataTrigger.Conditions>
             <Setter Property="Background" Value="Red"/>
             <Setter Property="Foreground" Value="Black"/>
         </MultiDataTrigger>
    </Style.Triggers>
</Style>

我需要以下内容，但这当然不起作用，因为Triggers仅支持Equal运算符。

<Style>
    <Style.Triggers>
        <MultiDataTrigger>
             <MultiDataTrigger.Conditions>
                  <!--<Condition 1 here.../>-->
                  <!--<Condition 2 here.../>-->
                  <Condition Binding="{Binding Path=id}" Value<>"3"/>
             </MultiDataTrigger.Conditions>
             <Setter Property="Background" Value="Red"/>
             <Setter Property="Foreground" Value="Black"/>
         </MultiDataTrigger>
    </Style.Triggers>
</Style>

Answer 1

您需要IValueConverter和一些额外的标记：

    <Style>
        <Style.Triggers>
            <MultiDataTrigger>
                <MultiDataTrigger.Conditions>
                    <!--<Condition 1 here.../>-->
                    <!--<Condition 2 here.../>-->
                    <Condition>
                        <Condition.Binding>
                            <Binding Path="id" Converter="{StaticResource ValueToEqualsParameterConverter}">
                                <Binding.ConverterParameter>
                                    <System:Int32>3</System:Int32>
                                </Binding.ConverterParameter>
                            </Binding>
                        </Condition.Binding>
                        <Condition.Value>
                            <System:Boolean>False</System:Boolean>
                        </Condition.Value>
                    </Condition>
                </MultiDataTrigger.Conditions>
                <Setter Property="Background" Value="Red" />
                <Setter Property="Foreground" Value="Black" />
            </MultiDataTrigger>
        </Style.Triggers>
    </Style>

转换器：

public class ValueToEqualsParameterConverter : IValueConverter {
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { 
        return value == parameter; 
    }
    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) { 
        return null; 
    }
}

Answer 2

另一种选择是将默认值定义为样式中的setter，然后实现数据触发器。在以下代码中，背景值始终为红色，除非值为3

＆＃13;

<Style>  
  <Setter Property="Background" Value="Red"/>
  <Setter Property="Foreground" Value="Black"/>
    <Style.Triggers>
        <MultiDataTrigger>
             <MultiDataTrigger.Conditions>
                  <!--<Condition 1 here.../>-->
                  <!--<Condition 2 here.../>-->
                  <Condition Binding="{Binding Path=id}" Value="3"/>
             </MultiDataTrigger.Conditions>
             <Setter Property="Background" Value="DefaultColor"/>
             <Setter Property="Foreground" Value="DefaultColor2"/>
         </MultiDataTrigger>
    </Style.Triggers>
</Style>

＆＃13;

条件不等于时触发

2 个答案: