How to export a high resolution chart image without maximising the WinForms

Dear support,

I have a ChartControl and I have implemented a context menu.

When I right-click on any area within the ChartControl, "Copy Image" button will show up.

The code below handles the "Copy Image" button click:

Visual Basic
' Copy Image function  
   Private Sub btnCopyImage_ItemClick(sender As System.Object, e As DevExpress.XtraBars.ItemClickEventArgs) Handles btnCopyImage.ItemClick   ' added on 5th Dec 2014  ' Joe  
       Dim originalSize As Size = mainChartCtrl.Size  
       Dim screenWidth As Integer = Screen.PrimaryScreen.Bounds.Width  
       Dim screenHeight As Integer = Screen.PrimaryScreen.Bounds.Height  
       Dim cloneChart As New ChartControl  

       Using ms As New IO.MemoryStream()  
           Try  
               cloneChart = CType(mainChartCtrl.Clone, ChartControl)  
               cloneChart.Size = New Size(screenWidth, screenHeight)   ' copy a high resolution image  
               cloneChart.ExportToImage(ms, System.Drawing.Imaging.ImageFormat.Png)  
               ms.Seek(0, SeekOrigin.Begin)  
               Using mf As New Bitmap(ms)  
                   Clipboard.SetImage(mf)  
               End Using  

           Finally  
               ms.Close()  
               cloneChart.Dispose()  
               XtraMessageBox.Show("This chart has been copied to the clipboard as an image.", "Copy Image", MessageBoxButtons.OK, MessageBoxIcon.Information)  

           End Try  
       End Using  
   End Sub  


Private Sub mainChartCtrl_CustomDrawSeriesPoint(sender As Object, e As DevExpress.XtraCharts.CustomDrawSeriesPointEventArgs) Handles mainChartCtrl.CustomDrawSeriesPoint    ' added on 2nd Dec 2014  ' Joe  
       Dim selectString As String, whatNodeText As String, whatContributionText As String, resultRows() As DataRow  

       If mainChartCtrl.Series(0).Visible = True Then  
           whatNodeText = e.LegendText  
           whatContributionText = e.LabelText  
           selectString = "Node = '" & whatNodeText & "'" & " " & "AND" & " " & "Contribution = " & whatContributionText  
           resultRows = MainDataTable.Select(selectString)   ' look for the datarow using Select function  
           resultRows(0)("Colour") = e.SeriesDrawOptions.Color  

       End If  
   End Sub  


Private Sub mainChartCtrl_CustomDrawSeries(sender As Object, e As DevExpress.XtraCharts.CustomDrawSeriesEventArgs) Handles mainChartCtrl.CustomDrawSeries   ' edited on 5th Dec 2014  ' Joe  
       Dim selectString As String, resultRows() As DataRow  
       Dim parentPartID As Integer  

       If mainChartCtrl.Series(1).Visible = True Then  
           parentPartID = CInt(mainChartCtrl.Series(1).Tag)  
           selectString = "PartID = '" & parentPartID.ToString & "'"  
           resultRows = MainDataTable.Select(selectString)  

           If resultRows.Length > 0 Then  
               nestedLevelColour = CType(resultRows(0)("Colour"), Color)  
           End If  

           e.SeriesDrawOptions.Color = nestedLevelColour  ' set the colour tag  
           e.LegendDrawOptions.Color = nestedLevelColour ' set the legend colour  

           ' set the legend text  ' added on 5th Dec 2014  ' Joe  
            e.LegendText = GetCurrentSubsystemName(parentPartID)  

       End If  
   End Sub  

The code above works well as I can export a good high resolution chart image without maximising the WinForms which docks the ChartControl.

However the series point colour, chart legend in the image are different from the original chart control.

You may compare the original chart control image and the exported chart control image.

How can I prevent the series point colour and chart legend to be different when I export the image?

Thank you.