Question: Resize control to show all rows.

Option Explicit

Private ma_HeightsPreviewPx() As Long
Private ma_HeightsPx() As Long

Private Sub Command1_Click()
   Dim i As Long
   Dim l As Long, r As Long, t As Long, b As Long
   Dim l_Height As Long
   Dim l_NonReportArea As Long
   Dim lo_Selected As Collection
   Dim lo_Focused As ReportRow
   
   With Me.ReportControl1
      ' Set up storage for each row and preview height
      ReDim ma_HeightsPreviewPx(.Rows.Count - 1)
      ReDim ma_HeightsPx(.Rows.Count - 1)
   
      ' Force report control to fire Measurement events
      .SetCustomDraw xtpCustomMeasureRow + xtpCustomMeasurePreviewItem
      .Redraw  ' Seems to be required to force final tally to be correct
      
      ' Store the current row selection
      ' We will be stepping through each row to calculate row heights
      ' since only visible rows will return their height in pixels/raise measurement events
      Set lo_Selected = New Collection
      For i = 0 To .SelectedRows.Count - 1
         lo_Selected.Add .SelectedRows.Row(i)
      Next i
      Set lo_Focused = .FocusedRow
   
      ' Step through each row to force measurement of each row
      ' Perhaps this could be made more efficient by using MovePageDown
      ' But this is guaranteed to measure every row
      .Navigator.MoveFirstRow
      For i = 0 To .Rows.Count - 1
         l_Height = l_Height + ma_HeightsPx(i) + ma_HeightsPreviewPx(i)
      
         .Navigator.MoveDown
      Next i
      
      ' Remove the measurement events
      .SetCustomDraw 0
      
      ' Release memory
      Erase ma_HeightsPreviewPx
      Erase ma_HeightsPx
      
      ' Restore the original row selections
      For i = 1 To lo_Selected.Count
         .SelectedRows.Add lo_Selected.Item(i)
      Next i
      Set .FocusedRow = lo_Focused
      
      ' Get height of visible report rows area (not including, headers, footers, etc..)
      .GetElementRect xtpReportElementRectReportArea, l, t, r, b
      ' Compute non-report height (header, footers, etc...)
      l_NonReportArea = (.Height / Screen.TwipsPerPixelY) - (b - t)
     
      ' Compute total required height
      .Height = Me.ScaleY(l_Height + l_NonReportArea, vbPixels, ScaleableScaleMode)
      
      ' Restore focus to the ReportControl
      .SetFocus
   End With
End Sub

Private Function ScaleableScaleMode() As ScaleModeConstants
   ' Make sure we don't raise an error when converting scalemodes for vbUser
   ScaleableScaleMode = IIf(Me.ScaleMode = vbUser, vbPixels, Me.ScaleMode)
End Function

Private Sub Form_Load()
   Dim i As Long
   
   With Me.ReportControl1

      .AutoColumnSizing = False
      
      .Columns.Add .Columns.Count, "Test", 150, True

      ' Generate Sample records
      For i = 1 To 13
         With .Records.Add
            .AddItem i
            If i Mod 2 = 0 Then
               .PreviewText = "Preview"
               If i Mod 4 = 0 Then
                  .PreviewText = .PreviewText & vbNewLine & "Preview"
               End If
               If i Mod 8 = 0 Then
                  .PreviewText = .PreviewText & vbNewLine & "Preview"
               End If
            End If
         End With
      Next i
      
      .PreviewMode = True
      
      .Populate
   End With
End Sub

Private Sub ReportControl1_MeasurePreviewItem(ByVal Row As XtremeReportControl.IReportRow, ByVal hDC As stdole.OLE_HANDLE, ByVal Width As Long, Height As Long)
   ' Store height of each preview row
   ma_HeightsPreviewPx(Row.Index) = Height
End Sub

Private Sub ReportControl1_MeasureRow(ByVal Row As XtremeReportControl.IReportRow, ByVal hDC As stdole.OLE_HANDLE, ByVal Width As Long, Height As Long)
   ' Store height of each row (not including preview height)
   ma_HeightsPx(Row.Index) = Height
End Sub