c# - 如何向 devexpress gridcontrol 添加自定义摘要项

Question

我在网格控件的页脚中有一个摘要字段。在网格控件中，我在第一列上有检查按钮，供用户选择要处理的记录。我需要修复汇总字段，仅对选定的行进行求和。现在它对每一行求和。我怎样才能只计算所选行的总和？

Answer 1

您需要更改GridColumn.SummaryItem.SummaryType属性至SummaryItemType.Custom并使用GridView.CustomSummaryCalculate事件来设置摘要的值。但是您无法在 GridView.CustomSummaryCalculate 事件中获取有关所选行的信息。这就是为什么您需要在 GridView.SelectionChanged 事件中计算总和，并在 GridView.CustomSummaryCalculate 事件中使用该总和。
这是示例:

private int _selectedSum;
private string _fieldName = "TOPLAM";

private void Form1_Load(object sender, EventArgs e)
{
    var column = gridView1.Columns[_fieldName];
    column.SummaryItem.SummaryType = SummaryItemType.Custom;
}

private void gridView1_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    var column = gridView1.Columns[_fieldName];

    switch (e.Action)
    {
        case CollectionChangeAction.Add:
            _selectedSum += (int)gridView1.GetRowCellValue(e.ControllerRow, column);
            break;
        case CollectionChangeAction.Remove:
            _selectedSum -= (int)gridView1.GetRowCellValue(e.ControllerRow, column);
            break;
        case CollectionChangeAction.Refresh:

            _selectedSum = 0;

            foreach (var rowHandle in gridView1.GetSelectedRows())
                _selectedSum += (int)gridView1.GetRowCellValue(rowHandle, column);

            break;
    }

    gridView1.UpdateTotalSummary();
}

private void gridView1_CustomSummaryCalculate(object sender, CustomSummaryEventArgs e)
{
    var item = e.Item as GridColumnSummaryItem;

    if (item == null || item.FieldName != _fieldName)
        return;

    if (e.SummaryProcess == CustomSummaryProcess.Finalize)
        e.TotalValue = _selectedSum;
}