Binding to DS error

vargasbo posted on Monday, July 17, 2006

I have the following bit of code...

I have a DataGridView, which is bound to a BindingSource. I then bind a child collection to the binding source, before doing so, I turn off the event listener, set the bS.Datasource to null, and then bind my new child collection.

When I do this, my application seems to just close without a single warning. I did get the application to crash before if I didn't turn off the event listener (call stack below), does anyone have any ideas?

Background: I'm using a third party tool to handle docking in my application. I did check the event log and the only item logged was a failure audit, but my object was loaded.

System.NullReferenceException was unhandled

  Message="Object reference not set to an instance of an object."

  Source="System.Windows.Forms"

  StackTrace:

       at System.Windows.Forms.DataGridViewRow.GetErrorText(Int32 rowIndex)

       at System.Windows.Forms.DataGridViewRow.Paint(Graphics graphics, Rectangle clipBounds, Rectangle rowBounds, Int32 rowIndex, DataGridViewElementStates rowState, Boolean isFirstDisplayedRow, Boolean isLastVisibleRow)

       at System.Windows.Forms.DataGridView.PaintRows(Graphics g, Rectangle boundingRect, Rectangle clipRect, Boolean singleHorizontalBorderAdded)

       at System.Windows.Forms.DataGridView.PaintGrid(Graphics g, Rectangle gridBounds, Rectangle clipRect, Boolean singleVerticalBorderAdded, Boolean singleHorizontalBorderAdded)

       at System.Windows.Forms.DataGridView.OnPaint(PaintEventArgs e)

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

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

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

       at System.Windows.Forms.DataGridView.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.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

       at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)

       at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)

       at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)

       at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)

       at System.Windows.Forms.Application.Run(Form mainForm)

RockfordLhotka replied on Monday, July 17, 2006

Are you also binding the parent object to another bindingsource? If so, you probably shouldn't set the child bindingsource to null, but rather to the parent bindingsource

http://www.lhotka.net/Cs2005Errata.aspx?id=6432c872-92ce-4bb8-bc26-b610b71956c8

I have run into similar null reference issues, and it is usually due to a linkage between data binding objects that triggers an attempted refresh of data when you don't have any data available because you've set something to null.

vargasbo replied on Monday, July 17, 2006

Yes, I do bind some properties of the customer to my form, while at the time I display the collections of address, invoices, etc in a datagridview.