本指南阐明如何使用 XRChart 控件，在分组报表中形象地显示数据。关于 XtraReports 中分组功能的信息，请参阅对数据分组主题。

每个行分组都有图表的报表是形象而信息丰富的。 GroupFooter(分组脚注) 带区是放置图表最常用也最合适的地方。为相应的分组标头插入分组脚注 (请参阅报表带区主题获得更多信息)。检查标头带区和脚注带区的 GroupBand.Level 值是否相等。把 XRChart 控件拖放到带区。规定 XRChart.DataSource 属性与报表的属性相同 (对于主/从报表 —— 与执行分组的报表的属性相同)。把数据系列添加到绘图，并按照需要定制其他图表元素。

如果现在正好运行项目，那么每个分组的图表都将是相同的，都显示数据集中的所有数据。其原因是 XRChart 控件独立于报表带区而取回数据。要使之与报表的分组同步，则需要为图表实现数据筛选。

通过接管 XRChart 控件的 BeforePrint 事件，可以完成此任务，如下列代码中所示。

C#	复制代码
private void xrChart1_BeforePrint(object sender, System.Drawing.Printing.PrintEventArgs e) { XRChart xrc = (XRChart)sender; // Gets the current value of the grouping field. // For the master-detail report use DetailBand.GetCurrentColumnValue in detail part instead. string filter_value = GetCurrentColumnValue("TheGroupingField").ToString(); // Clears the filters that may be set before. xrc.Series[0].DataFilters.Clear(); // Creates and adds a new filter on the data field "TheGroupingField" // that has the type System.String. // The condition is that the data value equals the filter_value parameter. xrc.Series[0].DataFilters.Add(new DataFilter("TheGroupingField", "System.String", DataFilterCondition.Equal, filter_value)); }

复制代码

private void xrChart1_BeforePrint(object sender, System.Drawing.Printing.PrintEventArgs e)
{
    XRChart xrc = (XRChart)sender;

    // Gets the current value of the grouping field.
    // For the master-detail report use DetailBand.GetCurrentColumnValue in detail part instead.
    string filter_value = GetCurrentColumnValue("TheGroupingField").ToString();

    // Clears the filters that may be set before.
    xrc.Series[0].DataFilters.Clear();

    // Creates and adds a new filter on the data field "TheGroupingField"
    // that has the type System.String. 
    // The condition is that the data value equals the filter_value parameter.
    xrc.Series[0].DataFilters.Add(new DataFilter("TheGroupingField", "System.String", 
        DataFilterCondition.Equal, filter_value));
}

Visual Basic	复制代码
Private Sub xrChart1_BeforePrint(ByVal sender As Object, _ ByVal e As System.Drawing.Printing.PrintEventArgs) Dim xrc As XRChart = CType(sender,XRChart) ' Gets the current value of the grouping field. ' For the master-detail report use DetailBand.GetCurrentColumnValue in detail part instead. Dim filter_value As String = GetCurrentColumnValue("TheGroupingField").ToString ' Clears the filters that may be set before. xrc.Series(0).DataFilters.Clear ' Creates and adds a new filter on the data field "TheGroupingField" ' that has the type System.String. ' The condition is that the data value equals the filter_value parameter. xrc.Series(0).DataFilters.Add(New DataFilter("TheGroupingField", "System.String", _ DataFilterCondition.Equal, filter_value)) End Sub

Visual Basic

复制代码

Private Sub xrChart1_BeforePrint(ByVal sender As Object, _ 
ByVal e As System.Drawing.Printing.PrintEventArgs)
    Dim xrc As XRChart = CType(sender,XRChart)

    ' Gets the current value of the grouping field.
    ' For the master-detail report use DetailBand.GetCurrentColumnValue in detail part instead.
    Dim filter_value As String = GetCurrentColumnValue("TheGroupingField").ToString

    ' Clears the filters that may be set before.
    xrc.Series(0).DataFilters.Clear

    ' Creates and adds a new filter on the data field "TheGroupingField" 
    ' that has the type System.String. 
    ' The condition is that the data value equals the filter_value parameter.
    xrc.Series(0).DataFilters.Add(New DataFilter("TheGroupingField", "System.String", _ 
    DataFilterCondition.Equal, filter_value))
End Sub

可以使用 AND 或 OR 连接运算符合并几个筛选。通过 DataFilterCollection.ConjunctionMode 属性 (属于 DataFilterCollection 对象)，或者通过系列的 SeriesBase.DataFiltersConjunctionMode 属性来指定它。当为系列创建一个或多个数据筛选对象时，所显示的系列将只包含满足筛选条件的数据点。