当属性值大于一定数量时触发 WPF

WPF Trigger when property value is greater than a certain amount

提问by Micah

I want to do something like this:

我想做这样的事情：

<ControlTemplate.Triggers>
    <Trigger Property="Width" Value=">25">
       <!-- Set values here -->
    </Trigger>
</ControlTemplate.Triggers>

Anyway to do something like this?

无论如何要做这样的事情？

采纳答案by Vasu Balakrishnan

You need a custom converter. Take a look at article

您需要一个自定义转换器。看看文章

回答by Daniel

You can use a data trigger and set the binding RelativeSource to Self. Data Triggers allow binding and bindings lets you have converters.

您可以使用数据触发器并将绑定 RelativeSource 设置为 Self。数据触发器允许绑定，绑定让您拥有转换器。

Example:

例子：

   <Button Content="I change colour depending on my width for some reason">
        <Button.Triggers>
            <DataTrigger
                Binding="{Binding
                Path=Width,
                RelativeSource={RelativeSource Self},
                Converter={StaticResource isLessThanConverter},
                ConverterParameter=50}"
                Value="True">
                <Setter Property="Button.Background" Value="Red" />
            DataTrigger>
        Button.Triggers>
    Button>

Reference

参考

回答by Sergey Aldoukhov

Not without code behind. Usual practice is:

并非没有背后的代码。通常的做法是：

• When working with UI elements, create an IValueConverter and bind to the property using the converter.
• When working with bound data, create a bool property on your data and trigger from that property.

• 使用 UI 元素时，创建 IValueConverter 并使用转换器绑定到属性。
• 使用绑定数据时，请在数据上创建 bool 属性并从该属性触发。

回答by Steven Robbins

Something might have been added in SP1, but the way I've achieved this in the past is with a ValueConvertor that converts the value into a boolean.

SP1 中可能添加了一些东西，但我过去实现这一点的方法是使用 ValueConvertor 将值转换为布尔值。

In your example your convertor would return true if the value was > 25, false otherwise. If that doesn't make sense I can put an example up :-)

在您的示例中，如果值 > 25，您的转换器将返回 true，否则返回 false。如果这没有意义，我可以举一个例子:-)

回答by Bhauraj Biradar

Data Trigger only validates exact value, not validates "evaluated values"(like greater than, less than, addition etc.). you need a converter to convert to exact value.

数据触发器仅验证精确值，而不验证“评估值”（如大于、小于、加法等）。您需要一个转换器来转换为精确值。