vb.net - DevExpress Xtra 报告：当细节带没有任何数据时，如何在组页脚中显示标签？

Question

如果有一个标签叫做：lblWarning。当详细信息带没有任何记录时，我想显示它（Visible = True）。标签位于组页脚中。

Answer 1

此事件附加到报告本身（在我的示例中，它被命名为 XtraReport1）。 GetCurrentRow()是一种XtraReportBase从主报表绑定源返回当前数据的方法。如果数据不存在，则返回 null。

private void XtraReport1_BeforePrint(object sender, PrintEventArgs e)
{
    bool noDataFound = GetCurrentRow() == null;

    lblWarning.Visible = noDataFound;
}

VB中的相同处理程序：

Private Sub XtraReport1_BeforePrint(ByVal sender As System.Object, ByVal e As PrintEventArgs) Handles MyBase.BeforePrint
    Dim noDataFound As Boolean = GetCurrentRow() Is Nothing

    lblWarning.Visible = noDataFound
End Sub

Answer 2

目前不在我的开发机器前面，但是这样的事情可能会起作用

Dim HadRecords As Boolean = False

Private Sub GroupFooter1_BeforePrint(ByVal sender As Object, ByVal e As System.Drawing.Printing.PrintEventArgs) Handles GroupFooter1.BeforePrint
    If HadRecords = False Then
        lblWarning.visible = True
    Else
        lblWarning.visible = False
        HadRecords = False ' reset the flag '
    End If
End Sub

Private Sub Detail_BeforePrint(ByVal sender As Object, ByVal e As System.Drawing.Printing.PrintEventArgs) Handles Detail.BeforePrint
    HadRecords = True ' set the flag '
End Sub