前台属性绑定不起作用 [英] Foreground property binding is not working

问题描述

我有一个文本块，文本的前景颜色应该按值改变。但是效果不好。

I have a textblock, the text's foreground's color should change by the value. However it is not working well.

<TextBlock Text="{Binding Path=Foo}" 
           Foreground="{Binding Path=Foo, Converter={StaticResource myConverter}" />

转换器部分喜欢

The converter part likes

public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        var temp = (int)value;
        if (temp <100 && temp>50)
        {
           return "#ff23d3";
        }
       if(temp>200)
           return "da2367";
       return new SolidBrush(Colors.Green);
    }

但是虽然值不同，但只返回一种颜色。



< b>我尝试过：



我在代码中设置了断点。它确实到了正确的位置。

也许类型转换错了？

But although the values are different, it only return one color.

What I have tried:

I set the break point in the code. It did reach the right place.
Maybe type conversion is wrong?

推荐答案

首先，Foreground [ ^ ] 依赖属性 [ ^ ]任何 WPF控件 [ ^ ]期待< a href =https：// msd n.microsoft.com/en-us/library/system.windows.media.brush(v=vs.110).aspx\">画眉 [ ^ ]。



有了这些知识，我们现在可以查看您的转换器：

First things first, the Foreground[^] Dependency Property[^] of the of any WPF Control[^] is expecting a Brush[^].

Armed with this knowledge, we can now look at your Converter:

public object Convert(object value,
                      Type targetType,
                      object parameter,
                      System.Globalization.CultureInfo culture)
{
    var temp = (int)value;
    if (temp <100 && temp>50)
    {
       return "#ff23d3";
    }
    if(temp>200)
       return "da2367";
    return new SolidBrush(Colors.Green);
}

1. ＃ff23d3 = string hex颜色值（不是颜色对象），不是任何类型的画笔。



2. da2367是一个字符串。与第一个不一样，但仍然不是画笔。



3. 新的SolidBrush（Colors.Green ） - 这是一种纯色画笔。这将有效。



因此，要修复，您需要将颜色值转换为颜色类 [ ^ ]可以与刷子一起使用：

1. "#ff23d3" = string hex color value (not color object), not a Brush of any kind.

2. "da2367" is a string. Not the same as the first, but still not a Brush.

3. new SolidBrush(Colors.Green) - This is a Solid Color Brush. This will work.

So, to fix, you need to convert a color value to a Color class[^] that can be used with a Brush:

using System.Windows.Media;

Color color = (Color)ColorConverter.ConvertFromString("#FFFF23D3");

现在你有了一个Color对象，你可以将它应用到的SolidColorBrush [< a href =https://www.google.com.au/search?safe=off&ei=qqEOWv-WO8it8QWjv5Y4&q=WPF+SolidColorBrush+class&oq=WPF+SolidColorBrush+class&gs_l=psy-ab。 3..0i30k1.770.1181.0.2083.2.2.0.0.0.0.495.755.2-1j0j1.2.0 .... 0 ... 1.1.64.psy-ab..0.2.753 ... 0i7i30k1.0.wdB_ -YzlZuEtarget =_ blanktitle =New Window> ^ ]：

Now that you have a Color object you can apply it to a SolidColorBrush[^]:

return new SolidBrush(color);

所以，你的固定转换呃将看起来像：

So, your fixed Converter will look like:

public object Convert(object value,
                     Type targetType,
                     object parameter,
                     System.Globalization.CultureInfo culture)
{
    var temp = (int)value;

    if (temp <100 && temp>50)
       return new SolidColorBrush(
           (Color)ColorConverter
               .ConvertFromString("#FFFF23D3"));

    if(temp>200)
       return new SolidColorBrush(
           (Color)ColorConverter
               .ConvertFromString("#FFDA2367"));

       return new SolidColorBrush(Colors.Green);
}

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