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445
Exception when Grid is drawn with DataSource
posted

Hello Team Infragistics,

I recently messed around with our companys way to use the UltraWinGrid.

In the past we did everything sequential...which is stupid as we provide a very bad user experience when using our software.

For example, we got a DataSource from our MSSQL Database which had about 3k entries and was retrieved via a pretty confusing (and tehrefore slow) view on the datbase. So, this would lock up the whole software and once the complete data was retrieved the UltraWinGrids DataSource was filled.

I changed this a little and am now using a delegate to get the DataSource in another thread. Once the thread is done I retrieve the data and assign it to the DataSource as usual.

Here is a small snippet on how we fill the DataSource:

    Me.m_Grid.BeginUpdate()
    Me.m_Grid.SuspendRowSynchronization()
 
    Me.m_Grid.DataSource = m_AsyncDataSource
 
    Me.m_Grid.ResumeRowSynchronization()
    Me.m_Grid.EndUpdate()

Now, what happens with my asynchronus attempt is that I get an exception when I
resize the software window while the DataSource is assigned.

I tried searching for the problem....but it seems to be a inner exception which I can't really solve.

Here's the exception:

System.NullReferenceException: Der Objektverweis wurde nicht auf eine Objektinstanz festgelegt.
   bei Infragistics.Win.UIElement.DrawChildElements(UIElementDrawParams& drawParams)
   bei Infragistics.Win.UIElement.DrawElement(UIElementDrawParams& defaultDrawParams)
   bei Infragistics.Win.UIElement.DrawChildElements(UIElementDrawParams& drawParams)
   bei Infragistics.Win.UIElement.DrawElement(UIElementDrawParams& defaultDrawParams)
   bei Infragistics.Win.UIElement.DrawChildElements(UIElementDrawParams& drawParams)
   bei Infragistics.Win.UIElement.DrawElement(UIElementDrawParams& defaultDrawParams)
   bei Infragistics.Win.UIElement.DrawChildElements(UIElementDrawParams& drawParams)
   bei Infragistics.Win.UIElement.DrawElement(UIElementDrawParams& defaultDrawParams)
   bei Infragistics.Win.UIElement.DrawHelper(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode, Boolean clipText, Boolean forceDrawAsFocused, Boolean preventAlphaBlendGraphics)
   bei Infragistics.Win.ControlUIElementBase.Draw(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode, Size elementSize, Boolean preventAlphaBlendGraphics)
   bei Infragistics.Win.ControlUIElementBase.Draw(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode)
   bei Infragistics.Win.UltraWinGrid.UltraGridUIElement.Draw(Graphics graphics, Rectangle invalidRectangle, Boolean doubleBuffer, AlphaBlendMode alphaBlendMode)
   bei Infragistics.Win.UltraControlBase.OnPaint(PaintEventArgs pe)
   bei Infragistics.Win.UltraWinGrid.UltraGrid.OnPaint(PaintEventArgs pe)
   bei System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer, Boolean disposeEventArgs)
   bei System.Windows.Forms.Control.WmPaint(Message& m)
   bei System.Windows.Forms.Control.WndProc(Message& m)
   bei System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   bei System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   bei System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Is there anything I missed?

I hope you can help me out here

TL;DR

1. Have a UltraWinGrid filled with a DataSource thatwas retrieved asynchronus

2. Resize the Program (and therefore the drawn area of the grid) while the DataSource of the Grid is filled and get above exception

I hope you can help me out here.

Thanks in advance

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  • 445
    posted

    I'm running into even more exceptions.

    When I have a filter columns filter control opened and then use a key-combination to refresh the grid (asynchronous) then once the refreshing ist done the filter control is broken.

    When I try to hide the filter row when the update starts I still get a error once the refreshing is done...

    My whole attempt for asynchronus refreshing seems to be very unstable...what would be the best way to do this?

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