Hi,
We are working in a grid with 'Outlook Group by' style.
In order to sort by summaries we use a custom 'Groupby' class using as example http://ko.infragistics.com/community/forums/p/9904/62322.aspx.
The problem appears when we group by a column with near 1500 different values, from 12000 rows. If i try to sort by summary column the grid takes more than 5 min to sort it. Is it normal?

I copy past the class and the call.

Public Class clsGroupByRowsSorter
    Implements IComparer
 
    Private Property _Column As UltraGridColumn
    Public Sub New(Column As UltraGridColumn)
        Me._Column = Column
    End Sub
 
    Private Function Compare(ByVal xObj As Object, ByVal yObj As Object) As Integer Implements IComparer.Compare
        If xObj.GetType = GetType(Infragistics.Win.UltraWinGrid.UltraGridGroupByRow) And yObj.GetType = GetType(Infragistics.Win.UltraWinGrid.UltraGridGroupByRow) Then
            Dim x As Infragistics.Win.UltraWinGrid.UltraGridGroupByRow = DirectCast(xObj, Infragistics.Win.UltraWinGrid.UltraGridGroupByRow)
            Dim y As Infragistics.Win.UltraWinGrid.UltraGridGroupByRow = DirectCast(yObj, Infragistics.Win.UltraWinGrid.UltraGridGroupByRow)
 
            Dim dblSummaryX As Double = 0
            Dim dblSummaryY As Double = 0
            Dim objSummaryX As String = x.Rows.SummaryValues(Me._Column.Key).Value.ToString
            Dim objSummaryY As String = y.Rows.SummaryValues(Me._Column.Key).Value.ToString
 
            If Double.TryParse(objSummaryX, dblSummaryX) AndAlso Double.TryParse(objSummaryY, dblSummaryY) Then
                Select Case Me._Column.SortIndicator
                    Case SortIndicator.Ascending
                        Return dblSummaryX.CompareTo(dblSummaryY)
                    Case SortIndicator.Descending
                        Return dblSummaryY.CompareTo(dblSummaryX)
                    Case Else
                        Return 0
                End Select
            Else
                Return 0
            End If
        Else
            Return Nothing
        End If
    End Function
End Class

    Private Sub sugCobro_AfterSortChange(sender As Object, e As Infragistics.Win.UltraWinGrid.BandEventArgs) Handles sugCobro.AfterSortChange
        For Each oCol As UltraGridColumn In Me.DisplayLayout.Bands(0).SortedColumns
            oCol.GroupByComparer = New clsGroupByRowsSorter(Me._LastColumnClicked)
        Next
    End Sub