如何将自定义摘要项添加到devexpress网格控件

Question

我在网格控件的页脚中有一个摘要字段。在网格控件中，我在第一列中有CheckButtons，供用户选择要处理的记录。我只需要将汇总字段修正为所选行的总和。现在它把每一行加起来。如何才能使它只与选定的行相加？

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Answer 1

您需要将GridColumn.SummaryItem.SummaryType属性更改为SummaryItemType.Custom，并使用GridView.CustomSummaryCalculate事件设置摘要的值。但无法获得有关GridView.CustomSummaryCalculate事件中选定行的信息。这就是为什么您需要在GridView.SelectionChanged事件中计算您的和，并在GridView.CustomSummaryCalculate事件中使用这个和。

下面是一个例子：

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;
}