WPF:绑定页边距/厚度左和顶部属性 [英] WPF: Binding Margin/Thickness Left and Top Property

问题描述

我遇到绑定问题(我知道为什么我会变成这个异常，但不知道如何解决此问题).

I got a problem with bindings(i know why am i becoming this exception but dunno how to solve the problem).

我已经尝试过这段代码.

I have tried this piece of code.

  <TextBlock HorizontalAlignment="Left" >
                        <TextBlock.Margin>
                            <Thickness Left="{Binding POSX.Value, Converter={StaticResource DPIConverter}}"
                                       Top="{Binding POSY.Value, Converter={StaticResource DPIConverter}}"/>
                        </TextBlock.Margin>
                    </TextBlock>

我遇到一个例外，它说，您无法绑定厚度[LEFT]，[TOP]属性.(例如，为什么:导致这些属性不是依赖属性)

Im getting an exception where it says that, u cant bind thickness [LEFT], [TOP] properties. (ik why : cause those properties are not Dependency Property)

感谢您的帮助.

以防万一您不了解我要达到的目标

Edit : In case you didnt understand what am i trying to reach

->我想绑定边距的左侧和顶部属性<-

-> I want to bind Left and Top Properties of Margin <-

推荐答案

是的，您不能绑定Left，Top，right或Bottom，因为它们不是依赖项属性.它们是CLR财产.DependencyProperty是CLR属性的包装.

That's right you can't bind Left,Top,right or Bottom, because they are not dependency property. They are CLR property. DependencyProperty is wrapper to CLR Property.

定义依赖项属性的类必须从DependencyObject类继承.厚度是一个不从DependencyObject类继承的类.但是Margin是从TextBlock继承的，TextBlock是从FrameworkElement继承的，而FrameworkElement是从UIElement继承的，UIElement是从Visual继承的，Visual是从DependencyObject类继承的.

Class which defines a dependency property must be inherited from the DependencyObject class. Thickness is a class which is not inherited from DependencyObject class. But the Margin is from TextBlock, which is inherited from FrameworkElement , and FrameworkElement inherited from UIElement, and UIElement is inherited from Visual which inherits from DependencyObject class.

您可以绑定的是Margin，因为Margin是在FrameworkElement类中注册的依赖项属性.

What you can bind is Margin, since Margin is a dependency Property registered in FrameworkElement Class.

您可以这样更改Xaml(示例代码)

You can change your Xaml like this (sample code)

<TextBlock HorizontalAlignment="Left" Margin="{Binding POS, Converter={StaticResource DPIConverter}}" >

下面是转换器代码，我们可以在其中发送整个厚度

Below is the converter code, where we can send the whole thickness

 public class DPIConverter : IValueConverter
{
    public object Convert(object value, System.Type targetType, object parameter,
        System.Globalization.CultureInfo culture)
    {    // your code inside Ivalue 
         // based pn some value send left and right value. other's can zero 
         // or which ever value you need. 
          int x = POS.PosX.Value;
          int y = POS.PoxY.Value;

        return new Thickness(System.Convert.ToDouble(x), System.Convert.ToDouble(y), 0, 0);
    }

    public object ConvertBack(object value, System.Type targetType,
        object parameter, System.Globalization.CultureInfo culture)
    {
        return null;
    }
}

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