Object crystal report对象引用未设置为对象的实例

我的crystal报告一直在说这个错误：

{“对象引用未设置为对象的实例。”}

堆栈跟踪：

at CrystalDecisions.Windows.Forms.PageControl.OnMouseMove(MouseEventArgs e)
   at System.Windows.Forms.Control.WmMouseMove(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at System.Windows.Forms.UserControl.WndProc(Message& m)
   at CrystalDecisions.Windows.Forms.PageControl.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 MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& 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& handled)
   at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& 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& 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()

有时它会加载，大多数时候它会这么说。似乎在交替地说。就像我重新运行报告一样，它按照预期的方式加载报告，然后在第二次运行时不会加载。怎么了

它在以下代码中停止： crview.ShowDialog（）

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为了给大家提供背景信息，我将数据集源与otehr报告使用相同的数据集源。但是其他的报道并没有出现这种问题。谁能告诉我？谢谢。

虽然这是一个较旧的线程，但下面是我解决问题的方法

我发现我有一个文本框，其中的公式超出了页面的范围。因此，它导致使用空字符串创建一个新页面。公式正在崩溃，并导致以下错误：

System.NullReferenceException未处理 Message=对象引用未设置为对象的实例

我只是偶尔看到一次，因为返回的值有时会导致TextObject增长

为了解决这个问题

• 我可以修正公式来处理空值，尽管它仍然会导致额外的空白页
• 将文本框重新放置在我的页面大小范围内，并将CanGrow设置为False

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我选择了两者，因为用户可能会无意中通过从打印机中选择较小的纸张大小而导致空白页面

升级到Crystal Reports for Visual Studio可再分发版本13\u 0\u 3为我解决了这个问题

解决了！ 我有这个问题很多年了！ 我使用数据集作为报告源。最后，在尝试了我在论坛上找到的所有解决方案后，我自己找到了答案：数据集包含空值，因此我只需将数据集字符串字段设置为DefaultValue:“”而不是DBNull。。。非常简单，但有效

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希望这有帮助。

在我的例子中，我删除了

reportDocument.Dispose（）并且它工作得很好
是的，我确实像这样实例化了crview:CrystalReportViewerUC crview=new CrystalReportViewerUC（）；SetReportPathFile（reportPath）；BuildDataTable（ds，dsName）；试图看到所有的都有值而不是空我也有同样的问题。你已经解决了吗？对不起，我还没有。我就让它这样吧。无论如何，在部署/安装的应用程序中，这不会发生。只有在使用VS运行pc时，才能在pc上进行调试/运行时。