MSB0001:内部MSBuild错误：任务实例应为null

因此，我最近开始使用Framework4.0的MSBUILD api。每当我尝试构建解决方案时，我的一个项目都会在总体结果失败Microsoft.build.Execution.BuildResultCode中返回失败。只有一个项目失败，其余所有项目都成功构建。向下隐藏的是异常-MSB0001:内部MSBuild错误：任务实例应为null。这是堆栈：

StackTrace  "   at Microsoft.Build.Shared.ErrorUtilities.ThrowInternalError(String message, Exception innerException, Object[] args)\r\n   at Microsoft.Build.Shared.ErrorUtilities.VerifyThrow(Boolean condition, String unformattedMessage)\r\n   at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.CleanupForTask()\r\n   at Microsoft.Build.BackEnd.TaskBuilder.<ExecuteTask>d__5.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()\r\n   at Microsoft.Build.BackEnd.TaskBuilder.<ExecuteTask>d__0.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()\r\n   at Microsoft.Build.BackEnd.TargetEntry.<ProcessBucket>d__16.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()\r\n   at Microsoft.Build.BackEnd.TargetEntry.<ExecuteTarget>d__0.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.GetResult()\r\n   at Microsoft.Build.BackEnd.TargetBuilder.<ProcessTargetStack>d__1b.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.GetResult()\r\n   at Microsoft.Build.BackEnd.TargetBuilder.<BuildTargets>d__0.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()\r\n   at Microsoft.Build.BackEnd.RequestBuilder.<BuildProject>d__26.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()\r\n   at Microsoft.Build.BackEnd.RequestBuilder.<BuildAndReport>d__16.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.GetResult()\r\n   at Microsoft.Build.BackEnd.RequestBuilder.<RequestThreadProc>d__12.MoveNext()"   string

Microsoft.Build.Shared.ErrorUtilities.ThrowInternalError（字符串消息，异常innerException，对象[]参数）\r\n Microsoft.Build.Shared.ErrorUtilities.VerifyThrow（布尔条件，字符串未格式化消息）\r\n位于Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ItaskeExecutionHost.CleanupFortTask（）\r\n位于Microsoft.Build.BackEnd.TaskBuilder.d_u5.MoveNext（）\r\n---从引发异常的上一个位置开始的堆栈结束跟踪----\r\n位于System.Runtime.CompilerServices.TaskWaiter.ThrowForOnSuccess（任务任务）\r\n在System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务任务）\r\n在System.Runtime.CompilerServices.TaskAwaiter`1.GetResult（）\r\n在Microsoft.Build.BackEnd.TaskBuilder.d_0.MoveNext（）上\r\n----从引发异常的上一个位置开始的堆栈结束跟踪----\r\n在System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务任务）\r\n在System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务任务任务任务）\r\n在System.Runtime.CompilerServices.TaskAwaiter`1.GetResult（）\r\n位于Microsoft.Build.BackEnd.TargetEntry.d\u 16.MoveNext（）\r\n--来自引发异常的上一个位置的堆栈结束跟踪----\r\n位于System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）\r\n位于System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务任务）\r\n在System.Runtime.CompilerServices.TaskAwaiter`1.GetResult（）\r\n在Microsoft.Build.BackEnd.TargetEntry.d\u 0.MoveNext（）\r\n---从引发异常的上一个位置开始的堆栈结束跟踪----\r\n在System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）\r\n位于System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务任务）\r\n位于System.Runtime.CompilerServices.TaskAwaiter.GetResult（）\r\n位于Microsoft.Build.BackEnd.TargetBuilder.d_1b.MoveNext（）\r\n---从引发异常的上一个位置开始的堆栈结束跟踪----\r\n在System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务任务）\r\n在System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务任务任务任务）\r\n在System.Runtime.CompilerServices.TaskAwaiter.GetResult（）\r\n在Microsoft.Build.BackEnd.TargetBuilder.d\u 0.MoveNext（）\r\n--从引发异常的上一个位置开始的堆栈结束跟踪----\r\n在System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务任务）\r\n在System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务任务任务任务任务）\r\n在System.Runtime.CompilerServices.TaskAwaiter`1.GetResult（）\r\n在Microsoft.Build.BackEnd.RequestBuilder.d\u 26.MoveNext（）\r\n---从引发异常的上一个位置开始的堆栈结束跟踪----\r\n在System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）\r\n在System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务任务）\r\n在System.Runtime.CompilerServices.TaskAwaiter`1.GetResult（）\r\n在Microsoft.Build.BackEnd.RequestBuilder.d_16.MoveNext（）上\r\n---从引发异常的上一个位置开始的堆栈结束跟踪----\r\n在System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务任务）\r\n在System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务任务任务任务）\r\n在System.Runtime.CompilerServices.TaskAwaiter.GetResult（）\r\n位于Microsoft.Build.BackEnd.RequestBuilder.d_u12.MoveNext（）“字符串

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当我使用Visual Studio的开发引擎或命令行进行构建时，它工作正常，没有错误。我真的很困惑是什么导致了这一切。我想了解一下。

我相信您已经实现了ITask接口，但没有排除抛出异常。您只需这样设置方法：

 public IBuildEngine BuildEngine
    { get; set; }

    public ITaskHost HostObject
    { get; set; }