如何用一些颜色填充矩形，使用渐变但仅作为工具（没有可见渐变）？

Question

我正在为矩形的 "Fill" 属性制作转换器，以用不同的颜色填充它。

所以我有一个关于某人缺席日期的信息列表。如果一个人在一段时间内不在，则矩形的不同部分必须用color1填充，否则用color2填充。对于 FOR 中的每个人，我计算日期之间的差异并填充渐变停止点，如：color1-border-color2-border-color1 ... 我试着让边框几乎不可见。

转换器：

 double bufferOffset = 0.0;
 double taskPeriodInDays = (endDate.Value.Date - 
 startDate.Value.Date).TotalDays;
 List<double> timeSections = new List<double>();

 for (int i = 1; i < absencesDatesBetweenStartAndEnd.Count; i++)
    {
       IsAbsent = !IsAbsent;
       GradientStop color = new GradientStop();
       GradientStop border = new GradientStop();
       border.Color = Colors.Black;

   color.Color = IsAbsent ? Colors.Orange : Colors.Violet;


   color.Offset = i == 1 ? 0 : bufferOffset;
   gradient.GradientStops.Add(color);

   color.Offset = bufferOffset + (absencesDatesBetweenStartAndEnd[i].Date - absencesDatesBetweenStartAndEnd[i - 1].Date).TotalDays / taskPeriodInDays;
   gradient.GradientStops.Add(color);

  if(i == absencesDatesBetweenStartAndEnd.Count - 1)
   {
      break;
   }

        border.Offset = color.Offset + 0.00001;
        gradient.GradientStops.Add(border);

        border.Offset = border.Offset + 0.00001;
        gradient.GradientStops.Add(border);

        bufferOffset = border.Offset;
   }
   return gradient;

<Rectangle Fill="{Binding Converter={StaticResource TaskExecutorAbsenceColorConverter}}"/>

硬编码 XAML 用于尝试值：

<Rectangle.Fill>
   <LinearGradientBrush StartPoint="0 0" EndPoint="1 0">
      <GradientStop Color="red" Offset="0"/>
      <GradientStop Color="red" Offset="0.065573770491803282"/>
      <GradientStop Color="black" Offset="0.065583770491803278"/>
      <GradientStop Color="black" Offset="0.065593770491803274"/>
      <GradientStop Color="blue" Offset="0.065593770491803274"/>
      <GradientStop Color="blue" Offset="0.29510196721311477"/>
      <GradientStop Color="black" Offset="0.29511196721311478"/>
      <GradientStop Color="black" Offset="0.29512196721311479"/>
      <GradientStop Color="red" Offset="0.29512196721311479"/>
      <GradientStop Color="red" Offset="0.36069573770491808"/>
      <GradientStop Color="black" Offset="0.36070573770491809"/>
      <GradientStop Color="black" Offset="0.3607157377049181"/>
      <GradientStop Color="blue" Offset="0.3607157377049181"/>
      <GradientStop Color="blue" Offset="0.50825672131147548"/>
      <GradientStop Color="black" Offset="0.50826672131147543"/>
      <GradientStop Color="black" Offset="0.50827672131147539"/>
      <GradientStop Color="red" Offset="0.50827672131147539"/>
      <GradientStop Color="red" Offset="1.00008"/>
   </LinearGradientBrush>
</Rectangle.Fill>

转换器工作不正常。渐变可见。

如您所见，我尝试将 gradientstops 的值放入 XAML，在这种情况下效果很好。我不明白为什么。

Hardcoding values in XAML Using converter

Answer 1

可能最合适的方法是使用带有彩色矩形的 ItemsControl。但是如果你仍然想要一个画笔，你可以像这样使用视觉画笔：

public class Conv : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        VisualBrush result = new VisualBrush();
        result.Stretch = Stretch.Fill;
        StackPanel container = new StackPanel();
        container.Orientation = Orientation.Horizontal;

        //Generate a colored rectangle for each day.
        //I just use some random values for illustration.
        Random rnd = new Random();
        for (int i = 0; i < 10; i++)
        {
            Rectangle rect = new Rectangle();
            rect.Width = 20;
            rect.Height = 20;
            rect.Fill = rnd.Next() % 2 == 0 ? Brushes.Red : Brushes.Green;
            container.Children.Add(rect);
        }
        result.Visual = container;
        return result;
    }

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

如何用一些颜色填充矩形，使用渐变但仅作为工具（没有可见渐变）？

How to fill the rectangle with some colors, using gradient but only as a tool(without visible gradient)?

c#

wpf

xaml

gradient

converters