wpf 当条件不等于时触发
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Trigger when condition is not equal to
提问by Nuts
I need a Styleunder WPF that sets several properties when multiple conditions are fullfilled. However, one of my conditions is of type Not Equal To. How should I change the below Styleso that the condition would become Not Equal To? Can it be even achieved without IValueConverter?
我需要一个Styleunder WPF，它在满足多个条件时设置多个属性。但是，我的条件之一是类型Not Equal To。我应该如何更改以下内容Style以使条件变为Not Equal To？没有它甚至可以实现IValueConverter吗？
<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>
I would need the below but this of course don't work since Triggers only support Equaloperator.
我需要以下内容，但这当然不起作用，因为触发器仅支持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>
回答by Ross
You need an IValueConverterand some extra markup for this:
IValueConverter为此，您需要一个和一些额外的标记：
<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>
And the converter:
和转换器：
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;
}
}
回答by Disha
Another option is to define default value as setter in style and then implement data trigger. In following code, the background value is always red except when value is 3
另一种选择是在样式中将默认值定义为 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
<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>