.net - 如何向 DevExpress XtraGrid 添加加权平均摘要？

Question

DevExpress Grid (XtraGrid) 允许网格及其组进行汇总计算。可用选项包括计数、最大值、最小值、平均值、总和、无和自定义。

有没有人得到一些示例代码，显示如何根据另一列中作为值提供的权重来计算加权平均列？

Answer 1

我最终解决了这个问题，并将在此处发布我的解决方案，以防其他人发现它有用。

如果加权平均值同时包含一个值和每行的权重，则包含该值的列应将权重 GridColumn 对象分配给其 Tag 属性。然后，这个事件处理程序将完成剩下的工作:

private static void gridView_CustomSummaryCalculate(object sender, CustomSummaryEventArgs e)
{
    GridColumn weightColumn = ((GridSummaryItem)e.Item).Tag as GridColumn;

    if (weightColumn == null)
        return;

    switch (e.SummaryProcess)
    {
        case CustomSummaryProcess.Start:
        {
            e.TotalValue = new WeightedAverageCalculator();
            break;
        }
        case CustomSummaryProcess.Calculate:
        {
            double size = Convert.ToDouble(e.FieldValue);
            double weight = Convert.ToDouble(((GridView)sender).GetRowCellValue(e.RowHandle, weightColumn));

            ((WeightedAverageCalculator)e.TotalValue).Add(weight, size);
            break;
        }
        case CustomSummaryProcess.Finalize:
        {
            e.TotalValue = ((WeightedAverageCalculator)e.TotalValue).Value;
            break;
        }
    }
}

private sealed class WeightedAverageCalculator
{
    private double _sumOfProducts;
    private double _totalWeight;

    public void Add(double weight, double size)
    {
        _sumOfProducts += weight * size;
        _totalWeight += weight;
    }

    public double Value
    {
        get { return _totalWeight==0 ? 0 : _sumOfProducts / _totalWeight; }
    }
}

该代码假定基础列值可以通过 Convert.ToDouble(object) 转换为 double 值。 .