绘制列图,列之间没有空格

Question

我正在使用WPF工具包,我正在尝试渲染一个看起来像直方图的图形.特别是,我希望每列都与每个列相对应.列之间应该没有间隙.

创建列图时,您应用了许多组件.(参见下面的示例XAML).有没有人知道你是否可以在其中一个元素上设置属性,这些元素指的是列之间的空白宽度？

                <charting:Chart Height="600" Width="Auto" HorizontalAlignment="Stretch" Name="MyChart"
                    Title="Column Graph" LegendTitle="Legend">

                    <charting:ColumnSeries 
                        Name="theColumnSeries"
                        Title="Series A"
                        IndependentValueBinding="{Binding Path=Name}"                
                        DependentValueBinding="{Binding Path=Population}"
                        Margin="0"
                        >
                    </charting:ColumnSeries>

                    <charting:Chart.Axes>
                        <charting:LinearAxis 
                            Orientation="Y" 
                            Minimum="200000" 
                            Maximum="2500000" 
                            ShowGridLines="True" />
                        <charting:CategoryAxis
                            Name="chartCategoryAxis"
                            />
                    </charting:Chart.Axes>
                </charting:Chart>

Answer 1

在没有神奇的答案的情况下,我从codeplex下载了wpftoolkit代码.

通过阅读代码,我可以在方法ColumnSeries.UpdateDataPoint中看到,有这行代码:

    double segmentWidth = coordinateRangeWidth * 0.8;

所以这是一个非常明确的"否",你不能通过设置公共属性来改变列之间的差距.

我将尝试的解决方案是编写一个继承自ColumnSeries并覆盖UpdateDataPoint的新类.

稍后编辑

好的,我让它上班了.如果有人感兴趣,我已附上HistogramSeries类的完整代码.

public class HistogramSeries : ColumnSeries, ISeries
{
    protected override void UpdateDataPoint(DataPoint dataPoint)
    {
        // That set the height and width.
        base.UpdateDataPoint(dataPoint);
        // Now we override the part about setting the width
        object category = dataPoint.ActualIndependentValue;
        var coordinateRange = GetCategoryRange(category);
        double minimum = (double)coordinateRange.Minimum.Value;
        double maximum = (double)coordinateRange.Maximum.Value;
        double coordinateRangeWidth = (maximum - minimum);
        const int WIDTH_MULTIPLIER = 1; // Harcoded to 0.8 in the parent. Could make this a dependency property
        double segmentWidth = coordinateRangeWidth * WIDTH_MULTIPLIER;
        var columnSeries = SeriesHost.Series.OfType<ColumnSeries>().Where(series => series.ActualIndependentAxis == ActualIndependentAxis);
        int numberOfSeries = columnSeries.Count();
        double columnWidth = segmentWidth / numberOfSeries;
        int seriesIndex = columnSeries.IndexOf(this);
        double offset = seriesIndex * Math.Round(columnWidth) + coordinateRangeWidth * 0.1;
        double dataPointX = minimum + offset;
        double left = Math.Round(dataPointX);
        double width = Math.Round(columnWidth);
        Canvas.SetLeft(dataPoint, left);
        dataPoint.Width = width;
    }
    #region ISeries Members
    System.Collections.ObjectModel.ObservableCollection<object> ISeries.LegendItems
    {
        get { return base.LegendItems; }
    }
    #endregion
    #region IRequireSeriesHost Members
    ISeriesHost IRequireSeriesHost.SeriesHost
    {
        get { return base.SeriesHost;}
        set { base.SeriesHost = value; }
    }
    #endregion
}
// Copied from the DataVisualization library
// (It was an internal class)
static class MyEnumerableFunctions
{
    public static int IndexOf(this IEnumerable that, object value)
    {
        int index = 0;
        foreach (object item in that)
        {
            if (object.ReferenceEquals(value, item) || value.Equals(item))
            {
                return index;
            }
            index++;
        }
        return -1;
    }
}