c# - WPF DataGrid - 分级色标上的颜色单元格

Question

我想弄清楚是否有办法在色标上为单个单元格着色。特别是，我希望在以下内容中获得类似 Bonus 列的内容:

目前，我已经将我的数据网格的列背景属性设置为绑定(bind)到以下转换器:

        public class NameToBrushConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            double? input = value as double?;
            if(input<-5)
            {
                return Brushes.MediumVioletRed;
            }
            if(-5<=input && input<-0.5)
            { 
                return Brushes.IndianRed;
            }
            if (.5 <= input && input < 5)
            { 
                return Brushes.LightGreen; 
            }
            if (5 <= input)
            { 
                return Brushes.LawnGreen; 
            } 

             return DependencyProperty.UnsetValue;            
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotSupportedException();
        }
    }
}

有没有办法在不对值进行硬编码的情况下获得色标？

谢谢 - kcross

编辑:我也在尝试创建一个更好的红绿色标(即从负数到正数)，就眼睛而言不那么难受的色标....如果有人有任何建议对此也表示赞赏!

Answer 1

我创建了一个 ValueToBrushConverter。你可以这样使用它:

Background="{Binding Path=YourDoubleValue,
                     Converter={StaticResource ValueToBrushConverter},
                     ConverterParameter='YourMinDouble|YourMaxDouble'}"

这将创建一个从绿色 (YourMinDouble) 到红色 (YourMaxDouble) 的渐变色标，并为 YourDoubleValue 选择相关颜色。 YourMinDouble 可以是负数，但必须小于 YourMaxDouble。如果 YourDoubleValue 不在范围内，则返回 Brushes.Transparent。
根据您的需要定制它!

转换器类

[ValueConversion(typeof(double), typeof(Brush))]
class ValueToBrushConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        double number = (double)value;
        double min = 0;
        double max = 100;

        // Get the value limits from parameter
        try
        {
            string[] limits = (parameter as string).Split(new char[] { '|' });
            min = double.Parse(limits[0], CultureInfo.InvariantCulture);
            max = double.Parse(limits[1], CultureInfo.InvariantCulture);
        }
        catch (Exception)
        {
            throw new ArgumentException("Parameter not valid. Enter in format: 'MinDouble|MaxDouble'");
        }

        if (max <= min)
        {
            throw new ArgumentException("Parameter not valid. MaxDouble has to be greater then MinDouble.");
        }

        if (number >= min && number <= max)
        {
            // Calculate color channels
            double range = (max - min) / 2;
            number -= max - range;
            double factor = 255 / range;
            double red = number < 0 ? number * factor : 255;
            double green = number > 0 ? (range - number) * factor : 255;

            // Create and return brush
            Color color = Color.FromRgb((byte)red, (byte)green, 0);
            SolidColorBrush brush = new SolidColorBrush(color);
            return brush;
        }

        // Fallback brush
        return Brushes.Transparent;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}