Question

我的视图模型有一个像这样的PointCollection属性：

public class ViewModel : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    private PointCollection points;
    public PointCollection Points
    {
        get { return points; }
        set
        {
            points = value;
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Points)));
        }
    }
}

这通常显示为折线：

<Polyline Points="{Binding Points}" Stroke="Black" StrokeThickness="2"/>

如何有效地将其显示为单独圈子的集合？

Answer 1

使用如下所示的绑定转换器。它会转换IEnumerable<Point> 到由一组零长度线组成的StreamGeometry。这些被绘制为圆圈通过将StrokeStartLineCap和StrokeEndLineCap设置为Round的路径。

public class LinePointsConverter : IValueConverter
{
    public object Convert(
        object value, Type targetType, object parameter, CultureInfo culture)
    {
        var geometry = new StreamGeometry();
        var points = value as IEnumerable<Point>;

        if (points != null && points.Any())
        {
            using (var sgc = geometry.Open())
            {
                foreach (var point in points)
                {
                    sgc.BeginFigure(point, false, false);
                    sgc.LineTo(point, true, false);
                }
            }
        }

        return geometry;
    }

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

路径看起来像这样：

<Path Data="{Binding Points, Converter={StaticResource LinePointsConverter}}"
      Stroke="Black" StrokeThickness="5"
      StrokeStartLineCap="Round" StrokeEndLineCap="Round"/>

如何将点集合绘制为单独的圆圈？

1 个答案: