System::AccessViolationError

ezekiel · April 2009

Hi!

I have this weird error:
I'm trying to display a report that shows data from a DataTable. The rows in this datatable are inserted from various other datatables. When I click the "print" button the following happens:
- If I move the mouse before the report is displayed everything is OK
- If I don't move the mouse there is about 50% chance that I get a System::AccessViolationError with the following callstack:

at System.Windows.Forms.UnsafeNativeMethods.CallWindowProc(IntPtr wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at System.Windows.Forms.NativeWindow.DefWndProc(Message& m)
   at System.Windows.Forms.ToolTip.WndProc(Message& msg)
   at System.Windows.Forms.ToolTip.ToolTipNativeWindow.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.RunDialog(Form form)
   at System.Windows.Forms.Form.ShowDialog(IWin32Window owner)
   at FastReport.Report.RSAsY14dr(Boolean , Form , Form )
   at FastReport.Report.ShowPrepared(Boolean modal)
   at FastReport.Report.ShowPrepared(

This is the function that calls the ShowPrepared() function

private: System::Void PrintReport(String^ report_name, String^ table_name, DataTable^ dt){
           try{
               Report^ report = gcnew Report();

               report->Load(report_name);

               // register data source
               report->RegisterData(dt, table_name);
               report->GetDataSource(table_name)->Enabled = true;

               // set the databands datasource so it iterates trough all entries
               DataBand^ db1 = (DataBand^)report->FindObject("Data1");
               db1->DataSource = report->GetDataSource(table_name);
               
               if(report->Prepare())report->ShowPrepared();
             }
             catch(Exception^ ex){LOGEX(ex);}
           }

Seems kind of weird that a ToolTip throws the exception when the mouse doesn't move ... Any ideas?

EDIT: This ONLY happens with DataTables that are constructed "by hand" - the rows are inserted one by one. The datatables that are filled with queries to the DB work fine.

AlexTZ · April 2009

Hello,

Do you have an example that I can run and test?

ezekiel · April 2009

Sorry, the whole app is way too big to use for an example. I tried to recreate but is really hard (I even made a simple app that fills a datatable from two other but no luck). Is there any way I can put some function in the report code so it looks at the DataTable as it is registered or shown?

Where is the ToolTip present on the report control, the toolstrip ?

BTW, the report is indeed created, shown for about a second and then CRASH ...

EDIT: I am talking about the Preview control of course.

AlexTZ · April 2009

Try to disable standard progress window by setting the FastReport.Utils.Config.ReportSettings.ShowProgress to false. Maybe it will help. If it will not, I need an example to fix the problem.

ezekiel · April 2009

Hi!

I am working on a demo app to replicate the bug but its hard since there is data in the database and so on and so on ... I still believe the error is on my side but I thought the exception could help me ...

I will let you know if i succeed in replicating the error.

Bye

System::AccessViolationError

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