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我正在學習C＃2010中使用的書「Microsoft VS C＃2010 Step by Step」，其第27章介紹了Task Parallel Library。當我運行提供的'GraphDemo'項目時，我得到一個XamlParseException錯誤。 我在同一個異常上檢查了本網站上的多個線程，並設法深入瞭解內核異常，以便加載PerformanceCounter失敗。 由於擔心繫統的.NET Framework 4安裝出現問題，我將其修復爲原始狀態，但錯誤仍然存在。 奇怪的是，本書的其他讀者都沒有抱怨過這個問題;在我寫信給發佈商之後，作者讓我給他發送一個項目的zip文件，他聲稱他的機器運行良好。第27章還有7個其他項目，他們都在我的系統上拋出同樣的錯誤。XamlParseException停止項目
這產生異常的全文：
System.Windows.Markup.XamlParseException was unhandled
Message='The invocation of the constructor on type 'GraphDemo.GraphWindow' that matches the specified binding constraints threw an exception.' Line number '3' and line position '5'.
Source=PresentationFramework
LineNumber=3
LinePosition=5
StackTrace:
at System.Windows.Markup.XamlReader.RewrapException(Exception e, IXamlLineInfo lineInfo, Uri baseUri)
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.runTryCode(Object userData)
at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, 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.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.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.Application.RunDispatcher(Object ignore)
at System.Windows.Application.RunInternal(Window window)
at System.Windows.Application.Run(Window window)
at System.Windows.Application.Run()
at GraphDemo.App.Main() in E:\IT Books\Source Code Projects\Microsoft Visual C# 2010 Step By Step\Chapter 27\GraphDemo\GraphDemo\obj\x86\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.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()
InnerException: System.InvalidOperationException
Message=Cannot load Counter Name data because an invalid index '' was read from the registry.
Source=System
StackTrace:
at System.Diagnostics.PerformanceCounterLib.GetStringTable(Boolean isHelp)
at System.Diagnostics.PerformanceCounterLib.get_NameTable()
at System.Diagnostics.PerformanceCounterLib.get_CategoryTable()
at System.Diagnostics.PerformanceCounterLib.CounterExists(String category, String counter, Boolean& categoryExists)
at System.Diagnostics.PerformanceCounterLib.CounterExists(String machine, String category, String counter)
at System.Diagnostics.PerformanceCounter.InitializeImpl()
at System.Diagnostics.PerformanceCounter..ctor(String categoryName, String counterName, String instanceName, Boolean readOnly)
at System.Diagnostics.PerformanceCounter..ctor(String categoryName, String counterName)
at GraphDemo.GraphWindow..ctor() in E:\IT Books\Source Code Projects\Microsoft Visual C# 2010 Step By Step\Chapter 27\GraphDemo\GraphDemo\GraphWindow.xaml.cs:line 25
InnerException:
And this is the code pinpointed by the inner exception:
public GraphWindow()
{
InitializeComponent();
PerformanceCounter memCounter = new PerformanceCounter("Memory", "Available Bytes");
availableMemorySize = Convert.ToUInt64(memCounter.NextValue());
this.pixelWidth = (int)availableMemorySize/20000;
if (this.pixelWidth < 0 || this.pixelWidth > 15000)
this.pixelWidth = 15000;
this.pixelHeight = (int)availableMemorySize/40000;
if (this.pixelHeight < 0 || this.pixelHeight > 7500)
this.pixelHeight = 7500;
}
第25行是一個地方memCounter被初始化。
我會感激所有我能得到的幫助。