NullReferenceException is thrown in the GetFontCacheByFont method

Hello Andreas,
Thank you for the provided call-stack. It is difficult however, to determine the cause of the issue.
As far as I can see, the issue occurs when the Grid's data source is set in the RefreshData  method. Would you please share code of the RefreshData method or your UserControlList  control?
Also specify the version of our components you are using. If you are able to reproduce the issue stably, please provide us with a small sample that illustrates the issue. It will help us find the precise cause of the issue and appropriate solution.

I look forward to your response.

Hi Sasha, the code is rather simple and Items is a List(of Item) which is a very simple class.

Public Sub RefreshData()
        Try
            If InvokeRequired Then
                Me.Invoke(New CallRefreshView(AddressOf RefreshData))
            Else

GenerateBackgroundImages()
                isLoadingData = True
                Me.GridControl1.DataSource = Nothing
                Me.GridControl1.DataSource = Items
                If GridColText.OptionsColumn.FixedWidth = False Then
                    Me.GridColText.Width = Me.GridColText.GetBestWidth()
                End If

If bUsegroups Then
                    GridView1.ExpandAllGroups()
                End If
                notfirstclickafterrefresh = False
                bEventstarted = True
            End If

isLoadingData = False

Catch ex As Exception
            Log.ErrorMethod(ex)
            isLoadingData = False
        End Try
    End Sub

The error doesn't happen every time.

Hello Andreas,
Thank you for the code snippet. We are working on this issue, but we need additional time to analyze this situation. We will come back to this ticket as soon as we can. We appreciate your patience.

Hello,
Having researched all this information, we came to the conclusion that it's not enough to give a precise answer why the exception is thrown. The top method in your callstack may throw an exception only if the Graphics object is null. Currently, I suggest you use the Me.BeginInvoke method instead of the Me.Invoke one to make sure that the GUI thread isn't locked while your code is being executed. Please try it and let me know whether it helps.
If it doesn't help, could you please provide us with a project demonstrating your scenario and the issue? After we reproduce it on our side, we can find the cause of the exception and suggest you an appropriate way to avoid it.
I hope to hear from you soon.

Is there any update on this issue? I am getting it too

Type:
   System.NullReferenceException

Message:
   Object reference not set to an instance of an object.

StackTrace:
   at DevExpress.Utils.Text.FontsCache.GetFontCacheByFont(Graphics graphics, Font font)
   at DevExpress.Utils.Text.TextUtils.GetStringSize(Graphics g, String text, Font font, StringFormat stringFormat, Int32 maxWidth, Int32 maxHeight, IWordBreakProvider wordBreakProvider, Boolean& isCropped)
   at DevExpress.Utils.Text.TextUtils.GetStringSize(Graphics g, String text, Font font, StringFormat stringFormat, Int32 maxWidth, Int32 maxHeight, Boolean& isCropped)
   at DevExpress.Utils.Paint.XPaintMixed.CalcTextSize(Graphics g, String s, Font font, StringFormat strFormat, Int32 maxWidth, Int32 maxHeight, Boolean& isCropped)
   at DevExpress.Utils.Text.StringPainter.SetupSimpleString(StringInfo info, StringCalculateArgs e)
   at DevExpress.Utils.Text.StringPainter.Calculate(StringCalculateArgs e)
   at DevExpress.Utils.Drawing.FooterCellPainter.CalcTextSize(ObjectInfoArgs e)
   at DevExpress.Utils.Drawing.FooterCellPainter.CalcObjectMinBounds(ObjectInfoArgs e)
   at DevExpress.XtraGrid.Views.Grid.ViewInfo.GridViewInfo.CalcGroupFooterCellHeight()
   at DevExpress.XtraGrid.Views.Grid.ViewInfo.GridViewInfo.CalcGroupFooterHeight()
   at DevExpress.XtraGrid.Views.Grid.ViewInfo.GridViewInfo.CalcRectsConstants()
   at DevExpress.XtraGrid.Views.Grid.ViewInfo.GridViewInfo.CalcRects(Rectangle bounds, Boolean partital)
   at DevExpress.XtraGrid.Views.Grid.ViewInfo.GridViewInfo.CalcCore(Graphics g, Rectangle bounds)
   at DevExpress.XtraGrid.Views.Grid.ViewInfo.GridViewInfo.Calc(Graphics g, Rectangle bounds)
   at DevExpress.XtraGrid.Views.Base.ColumnView.DoInternalLayout()
   at DevExpress.XtraGrid.Views.Base.ColumnView.CalculateLayout()
   at DevExpress.XtraGrid.Views.Grid.GridView.LayoutChanged()