title: crystal report object reference not set to an instance of an object
body: <p>I have crystal reports that keeps saying this error:</p>
  
  <p>{"Object reference not set to an instance of an object."}</p>
  
  <p>Stacktrace:</p>
  
  <pre><code>at CrystalDecisions.Windows.Forms.PageControl.OnMouseMove(MouseEventArgs e)
     at System.Windows.Forms.Control.WmMouseMove(Message&amp; m)
     at System.Windows.Forms.Control.WndProc(Message&amp; m)
     at System.Windows.Forms.ScrollableControl.WndProc(Message&amp; m)
     at System.Windows.Forms.UserControl.WndProc(Message&amp; m)
     at CrystalDecisions.Windows.Forms.PageControl.WndProc(Message&amp; m)
     at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message&amp; m)
     at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message&amp; m)
     at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
     at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG&amp; msg)
     at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
     at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
     at System.Windows.Window.ShowHelper(Object booleanBox)
     at System.Windows.Window.Show()
     at System.Windows.Window.ShowDialog()
     at ADR.Forms.GALReport.GuardianAdLitemReport.btnPreviewReport() in C:\Users\user\Development\ProjectADR\ADR\Forms\CaseCoordinatorReports\GALReport\GuardianAdLitemReport.xaml.cs:line 527
     at ADR.Forms.GALReport.GuardianAdLitemReport.Button_Click(Object sender, RoutedEventArgs e) in C:\Users\user\Development\ProjectADR\ADR\Forms\CaseCoordinatorReports\GALReport\GuardianAdLitemReport.xaml.cs:line 90
     at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
     at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
     at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
     at System.Windows.UIElement.RaiseEvent(RoutedEventArgs e)
     at System.Windows.Controls.Primitives.ButtonBase.OnClick()
     at System.Windows.Controls.Button.OnClick()
     at System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
     at System.Windows.UIElement.OnMouseLeftButtonUpThunk(Object sender, MouseButtonEventArgs e)
     at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
     at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
     at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
     at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
     at System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent)
     at System.Windows.UIElement.OnMouseUpThunk(Object sender, MouseButtonEventArgs e)
     at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
     at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
     at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
     at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
     at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
     at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
     at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
     at System.Windows.Input.InputManager.ProcessStagingArea()
     at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
     at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
     at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
     at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean&amp; handled)
     at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean&amp; handled)
     at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean&amp; handled)
     at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
     at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
     at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
     at System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
     at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
     at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG&amp; msg)
     at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
     at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
     at System.Windows.Threading.Dispatcher.Run()
     at System.Windows.Application.RunDispatcher(Object ignore)
     at System.Windows.Application.RunInternal(Window window)
     at System.Windows.Application.Run(Window window)
     at System.Windows.Application.Run()
     at ADR.Program.Main() in C:\Users\user\Development\ProjectADR\ADR\Program.cs:line 57
     at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
     at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
     at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
     at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
     at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
     at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
     at System.Threading.ThreadHelper.ThreadStart()
  </code></pre>
  
  <p>Sometimes it loads, most of the time it says that. It seems to say that alternately. Like if I rerun the report, it loads the report as what is expected then does not on the second run. What is wrong? </p>
  
  <p>it stops in this code:
   crview.ShowDialog();</p>
  
  <p>To give you background, I am using dataset source the same with otehr reports. but other reports are not havign this kind of problem. Anyone who can tell me? thanks.</p>