Understanding the big red cross (X)

1425

Understanding the big red cross (X)

Richard posted over 13 years ago

Hi all,

I've witnessed this big red cross appearing in place of an UltraGrid when calls wern't marshalled correctly to the main/UI thread when making use of the control.

I have an application that I've ensured only accesses controls from the main/UI thread.

Recently, we've been stress-testing our application and have witnessed this red cross again. This time it appears in place of a ribbon/toolbar control. It's only ever appeared when we're using excessive amounts of memory - causing some components of the application to become sluggish. One example is when the user creates a scatter UltraChart component that has about 40,000 points of data.

So I have a couple of questions concerning this issue:

I've noticed different chart types have different thresholds for the amount of data they can use (understandably) e.g. a pie chart may start to be a bit slugglish when using more than 100 slices, whereas a scatter chart could cope with 1000 points quite comfortably. Is it normal for a scatter UltraChart to fall over with 40,000 points? Are there any general thresholds that have been established (I understand this is specific to ones PC, but if there are some rough numbers, it'd be much appreciated).
When creating this scatted chart with 40,000 points, it becomes very slow - especially when hovering over the chart to display tooltips etc. Could this cause the red cross to appear in the ribbon/toolbar due to lack of memory or CPU to repaint the controls properly? Maybe an OutOfMemoryException is being thrown in the ribbon/toolbar?

I'd appreciate any more information regarding this red cross. From what I've read so far:

It "almost always" occurs when a call is made to a control from another thread (not the main/UI thread it was constructed on).
It occurs when a control attempts to Paint itself and an exception occurs.

Any information what so ever (even simply to clarify my current understanding is correct) would be greatly appreciated.

Cheers,

Richard

1425

Richard posted over 13 years ago

Can anyone help with this? I've now noticed it can occur when using a low amount of memory, so that doesn't seem to affect it. The stack trace I'm getting from the unhandled exception is:

************** Exception Text **************

System.ArgumentException: Parameter is not valid.

   at System.Drawing.Graphics.GetHdc()

   at Infragistics.Win.FormattedLinkLabel.PositionElementsCache.MeasureTextGDIOrThemed(String text, Font font, TextFormatFlags textFormatFlags)

   at Infragistics.Win.FormattedLinkLabel.PositionElementsCache.MeasureCharacterRangesGDI(String text, Font font, TextFormatFlags textFormatFlags, CharacterRange[] ranges)

   at Infragistics.Win.FormattedLinkLabel.PositionElementsCache.ReMeasureParts(String text, Int32[] parts, Single[] widths, Int32 partStartIndex, Int32 partEndIndex, Font font, Single& lineHeight)

   at Infragistics.Win.FormattedLinkLabel.PositionElementsCache.MeasureParts(String text, Int32[] parts, Font font, Single& lineHeight)

   at Infragistics.Win.FormattedLinkLabel.NodeText.TextLayoutInfo.Measure(PositionElementsInfo& info)

   at Infragistics.Win.FormattedLinkLabel.NodeText.PositionSelf(PositionElementsInfo& info)

   at Infragistics.Win.FormattedLinkLabel.NodeBase.PositionHelper(PositionElementsInfo& info)

   at Infragistics.Win.FormattedLinkLabel.NodeBase.Position(PositionElementsInfo& info)

   at Infragistics.Win.FormattedLinkLabel.NodeBase.PositionChildNodes(PositionElementsInfo& info)

   at Infragistics.Win.FormattedLinkLabel.NodeBlock.PositionChildNodes(PositionElementsInfo& info)

   at Infragistics.Win.FormattedLinkLabel.NodeBase.PositionHelper(PositionElementsInfo& info)

   at Infragistics.Win.FormattedLinkLabel.NodeBase.Position(PositionElementsInfo& info)

   at Infragistics.Win.FormattedLinkLabel.NodeBase.PositionElements(IFormattedLinkLabelOwner owner, UIElement containerElem, Rectangle containerRect, Boolean calcIdealLayoutSize, Size& layoutSize)

   at Infragistics.Win.FormattedLinkLabel.FormattedTextUIElement.PositionElementsHelper(Rectangle layoutRect, Boolean setElemRectToIdealSize)

   at Infragistics.Win.FormattedLinkLabel.FormattedTextUIElement.PositionChildElements()

   at Infragistics.Win.UltraWinToolbars.RibbonCaptionUIElement.PositionChildElements()

   at Infragistics.Win.UIElement.VerifyChildElements(ControlUIElementBase controlElement, Boolean recursive)

   at Infragistics.Win.UIElement.VerifyChildElements(ControlUIElementBase controlElement, Boolean recursive)

   at Infragistics.Win.UIElement.VerifyChildElements(ControlUIElementBase controlElement, Boolean recursive)

   at Infragistics.Win.UIElement.VerifyChildElements(ControlUIElementBase controlElement, Boolean recursive)

   at Infragistics.Win.UIElement.DrawHelper(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode, Boolean clipText, Boolean forceDrawAsFocused, Boolean preventAlphaBlendGraphics)

   at Infragistics.Win.UIElement.Draw(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode, Boolean forceDrawAsFocused, Boolean preventAlphaBlendGraphics)

   at Infragistics.Win.ControlUIElementBase.Draw(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode, Size elementSize, Boolean preventAlphaBlendGraphics)

   at Infragistics.Win.ControlUIElementBase.Draw(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode, Size elementSize)

   at Infragistics.Win.ControlUIElementBase.Draw(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode)

   at Infragistics.Win.UltraControlBase.OnPaint(PaintEventArgs pe)

   at Infragistics.Win.UltraWinToolbars.UltraToolbarsDockArea.OnPaint(PaintEventArgs pe)

   at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer)

   at System.Windows.Forms.Control.WmPaint(Message& m)

   at System.Windows.Forms.Control.WndProc(Message& m)

   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)

   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)

   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
Cancel
Reply

Cancel
469350

Offline Mike Saltzman posted over 13 years ago in reply to Richard

The big red "X" occurs any time an exception occurs inside the OnPaint method of a control. Since the controls have been around so long and are so well-used and therefore well-tested, we rarely find bugs in the painting code any more. But it can happen.

Does the exception always occur with the same call stack which includes a reference to the FormattedLinkLabel?

Is the exception always on a call to GetHdc?

Or does the exception vary each time it occurs?

If the exception always happens on the same call to GetHdc being called from MeasureTextGDIOrThemed, then this is likely a bug in the FormattedLinkLabel.

If the exception varies each time it occurs, then it's probably a memory or threading issue.
Cancel
Reply

Cancel
1425

Richard posted over 13 years ago in reply to Mike Saltzman

Hi Mike,

Thanks for taking a look at this.

Mike Saltzman"]Does the exception always occur with the same call stack which includes a reference to the FormattedLinkLabel?

Yes, the call-stack in the exception is always exactly the same.

After having a look at it further, we established it was occuring when a Form containing an UltraExplorerBar is shown from the Form that contains the Ribbon. The item that was selected in the UltraExplorerBar when the Form was displayed last is selected upon displaying the Form (in the construct). The error occured intermitently, only when it selected an item in the bar that was not the default selected item. It always occured soon after displaying the form, but it could take up to 10 iterations of closing the form and reopening it too see the error.

To select the item in the explorer bar in the Form, we set the SelectedGroup of the explorer bar to the group that contained the appropriate item, and then checked the appropriate item.

I modified this so that instead, the ActiveGroup of the explorer bar is set to the group that contains the appropriate item. We perform the SelectActiveGroup action on the explorer bar using the PerformAction method, and then check the item in the same way. This appears to have worked!

So I'm guessing there's an issue relating to the focus of the groups or something?

Out of interest, does this still sound like a bug, or it simply bad practice to select things in an Infragistics Control by setting the SelectedX property e.g. SelectedGroup?

Thanks for the information Mike!

Cheers,

Richard
Cancel
Reply

Cancel
469350

Offline Mike Saltzman posted over 13 years ago in reply to Richard

Hi Richard,

Richard said:
Out of interest, does this still sound like a bug, or it simply bad practice to select things in an Infragistics Control by setting the SelectedX property e.g. SelectedGroup?

It's impossible to say for sure without being able to duplicate the issue. It could be a timing or threading issue, but it's certainly possible that it's a bug in the ExplorerBar. Perhaps setting the SelectedGroup is forcing it to paint too early before some part of the control has been properly initialized.

If you can reproduce the issue in a small sample project and post it here, we could look into it further.
Cancel
Reply

Cancel
1425

Richard posted over 13 years ago in reply to Mike Saltzman

Thanks Mike, I'll keep an eye out for it and when I get a chance I'll post a sample. Thanks for your help.

Richard
Cancel
Reply

Cancel