C# 未将对象引用设置为Object.Windows.forms控件的实例导致此问题

我有个例外

我为InitializeComponent（）创建了一个try-catch，如下所示

try
{
    InitializeComponent();
    Auto_Complete();
}
catch(Exception ex)
{
    System.Windows.Forms.MessageBox.Show(ex.Message);
}

然后我得到一个异常，说“对象引用未设置为对象的实例”

我在寻找错误的原因

然后我发现这个错误是由于我在xaml中添加了一个控件造成的

xmlns:wf="clr-namespace:System.Windows.Forms;assembly=System.Windows.Forms"
            <WindowsFormsHost Margin="272,10,396,42" Width="240">
                <wf:TextBox x:Name="txtAutoProductCode" AutoCompleteMode="SuggestAppend" AutoCompleteSource="CustomSource" />
            </WindowsFormsHost>

这是个例外

        System.Windows.Markup.XamlParseException was unhandled
  HResult=-2146233087
  Message='Initialization of 'Billing.MainWindow' threw an exception.' Line number '6' and line position '9'.
  Source=PresentationFramework
  LineNumber=6
  LinePosition=9
  StackTrace:
       at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri)
       at System.Windows.Markup.WpfXamlLoader.LoadBaml(XamlReader xamlReader, Boolean skipJournaledProperties, Object rootObject, XamlAccessLevel accessLevel, Uri baseUri)
       at System.Windows.Markup.XamlReader.LoadBaml(Stream stream, ParserContext parserContext, Object parent, Boolean closeStream)
       at System.Windows.Application.LoadBamlStreamWithSyncInfo(Stream stream, ParserContext pc)
       at System.Windows.Application.LoadComponent(Uri resourceLocator, Boolean bSkipJournaledProperties)
       at System.Windows.Application.DoStartup()
       at System.Windows.Application.<.ctor>b__1(Object unused)
       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.DispatcherOperation.InvokeImpl()
       at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Windows.Threading.DispatcherOperation.Invoke()
       at System.Windows.Threading.Dispatcher.ProcessQueue()
       at System.Windows.Threading.Dispatcher.WndProcHook(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.LegacyInvokeImpl(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 Billing.App.Main() in c:\Users\kamalmohan\Documents\Visual Studio 2012\Projects\Billing\Billing\obj\Debug\App.g.cs:line 0
       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.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: System.InvalidOperationException
       HResult=-2146233079
       Message=Cannot have nested BeginInit calls on the same instance.
       Source=PresentationFramework
       StackTrace:
        at System.Windows.FrameworkElement.BeginInit()
        at MS.Internal.Xaml.Runtime.ClrObjectRuntime.InitializationGuard(XamlType xamlType, Object obj, Boolean begin)
       InnerException: 

System.Windows.Markup.XamlParseException未处理
HResult=-2146233087
Message='Billing.MainWindow'的初始化引发异常。'行号'6'和行位置'9'。
Source=PresentationFramework
行号=6
LinePosition=9
堆栈跟踪：
在System.Windows.Markup.WpfXamlLoader.Load（XamlReader XamlReader、IXamlObjectWriterFactory writerFactory、Boolean skipJournaledProperties、Object rootObject、XamlObjectWriterSettings设置、Uri baseUri）
位于System.Windows.Markup.wpfxamloader.LoadBaml（XamlReader XamlReader、Boolean skipJournaledProperties、Object rootObject、XamlAccessLevel accessLevel、Uri baseUri）
位于System.Windows.Markup.XamlReader.LoadBaml（Stream-Stream，ParserContext-ParserContext，Object-parent，Boolean-closeStream）
在System.Windows.Application.LoadBamlStreamWithSyncInfo（流，ParserContext pc）
位于System.Windows.Application.LoadComponent（Uri resourceLocator，布尔bSkipJournaledProperties）
在System.Windows.Application.DoStartup（）中
在System.Windows.Application.b__1（未使用的对象）
位于System.Windows.Threading.ExceptionWrapper.InternalRealCall（委托回调、对象参数、Int32 numArgs）
位于MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen（对象源、委托方法、对象参数、Int32 numArgs、委托catchHandler）
在System.Windows.Threading.DispatcherOperation.InvokeImpl（）中
位于System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext（对象状态）
位于System.Threading.ExecutionContext.RunInternal（ExecutionContext ExecutionContext、ContextCallback回调、对象状态、布尔值preserveSyncCtx）
在System.Threading.ExecutionContext.Run（ExecutionContext ExecutionContext，ContextCallback回调，对象状态，布尔保存SyncCTX）
在System.Threading.ExecutionContext.Run（ExecutionContext ExecutionContext，ContextCallback回调，对象状态）
在System.Windows.Threading.DispatcherOperation.Invoke（）中
在System.Windows.Threading.Dispatcher.ProcessQueue（）中
位于System.Windows.Threading.Dispatcher.WndProcHook（IntPtr-hwnd、Int32-msg、IntPtr-wParam、IntPtr-lParam、Boolean和handled）
在MS.Win32.HwndWrapper.WndProc（IntPtr-hwnd、Int32-msg、IntPtr-wParam、IntPtr-lParam、Boolean和handled）
在MS.Win32.HwndSubclass.DispatcherCallbackOperation（对象o）上
位于System.Windows.Threading.ExceptionWrapper.InternalRealCall（委托回调、对象参数、Int32 numArgs）
位于MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen（对象源、委托方法、对象参数、Int32 numArgs、委托catchHandler）
位于System.Windows.Threading.Dispatcher.LegacyInvokeImpl（DispatcherPriority优先级、TimeSpan超时、委托方法、对象参数、Int32 numArgs）
位于MS.Win32.HwndSubclass.SubclassWndProc（IntPtr hwnd、Int32 msg、IntPtr wParam、IntPtr lParam）
位于MS.Win32.unsafentivemethods.DispatchMessage（MSG&MSG）
位于System.Windows.Threading.Dispatcher.PushFrameImpl（DispatcherFrame框架）
在System.Windows.Threading.Dispatcher.PushFrame（DispatcherFrame框架）上
在System.Windows.Threading.Dispatcher.Run（）中
位于System.Windows.Application.RunDispatcher（对象忽略）
位于System.Windows.Application.RunInternal（窗口）
在System.Windows.Application.Run（窗口）中
在System.Windows.Application.Run（）处
在c:\Users\kamalmohan\Documents\Visual Studio 2012\Projects\Billing\Billing\obj\Debug\App.g.cs中的Billing.App.Main（）处：第0行
位于System.AppDomain.\u nExecuteAssembly（RuntimeAssembly程序集，字符串[]args）
位于System.AppDomain.ExecuteAssembly（字符串汇编文件、证据汇编安全性、字符串[]args）
在Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly（）上
位于System.Threading.ThreadHelper.ThreadStart\u上下文（对象状态）
位于System.Threading.ExecutionContext.RunInternal（ExecutionContext ExecutionContext、ContextCallback回调、对象状态、布尔值preserveSyncCtx）
在System.Threading.ExecutionContext.Run（ExecutionContext ExecutionContext，ContextCallback回调，对象状态，布尔保存SyncCTX）
在System.Threading.ExecutionContext.Run（ExecutionContext ExecutionContext，ContextCallback回调，对象状态）
位于System.Threading.ThreadHelper.ThreadStart（）处
InnerException:System.InvalidOperationException
HResult=-2146233079
Message=不能在同一实例上嵌套BeginInit调用。
Source=PresentationFramework
堆栈跟踪：
位于System.Windows.FrameworkElement.BeginInit（）处
位于MS.Internal.Xaml.Runtime.ClrObjectRuntime.InitializationGuard（XamlType XamlType、对象obj、布尔begin）
内部异常：

这可能有助于您准确地找出问题所在

XAMLParseException是WPF中引发的常见异常。不幸的是 这没有多大帮助

要帮助找出真正的错误是什么，可以启用“异常” 在VisualStudio中更早地报告。默认的键组合是 Ctrl+Alt+E。然后，选中所有复选框

现在，代码中抛出的异常将在中突出显示 调试器

---

您确定这是由于控制而不是由于您在Auto_Complete（）中执行的操作吗？如果你确定的话。。您需要检查您是否在MessageBox.Show（）中的controlUse ex.ToString（）的构造函数中做了一些有趣的事情。这将显示完整的stac

        System.Windows.Markup.XamlParseException was unhandled
  HResult=-2146233087
  Message='Initialization of 'Billing.MainWindow' threw an exception.' Line number '6' and line position '9'.
  Source=PresentationFramework
  LineNumber=6
  LinePosition=9
  StackTrace:
       at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri)
       at System.Windows.Markup.WpfXamlLoader.LoadBaml(XamlReader xamlReader, Boolean skipJournaledProperties, Object rootObject, XamlAccessLevel accessLevel, Uri baseUri)
       at System.Windows.Markup.XamlReader.LoadBaml(Stream stream, ParserContext parserContext, Object parent, Boolean closeStream)
       at System.Windows.Application.LoadBamlStreamWithSyncInfo(Stream stream, ParserContext pc)
       at System.Windows.Application.LoadComponent(Uri resourceLocator, Boolean bSkipJournaledProperties)
       at System.Windows.Application.DoStartup()
       at System.Windows.Application.<.ctor>b__1(Object unused)
       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.DispatcherOperation.InvokeImpl()
       at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Windows.Threading.DispatcherOperation.Invoke()
       at System.Windows.Threading.Dispatcher.ProcessQueue()
       at System.Windows.Threading.Dispatcher.WndProcHook(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.LegacyInvokeImpl(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 Billing.App.Main() in c:\Users\kamalmohan\Documents\Visual Studio 2012\Projects\Billing\Billing\obj\Debug\App.g.cs:line 0
       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.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: System.InvalidOperationException
       HResult=-2146233079
       Message=Cannot have nested BeginInit calls on the same instance.
       Source=PresentationFramework
       StackTrace:
        at System.Windows.FrameworkElement.BeginInit()
        at MS.Internal.Xaml.Runtime.ClrObjectRuntime.InitializationGuard(XamlType xamlType, Object obj, Boolean begin)
       InnerException: