mscorlib.dll中的C＃System.OutOfMemoryException

Question

我正在使用VS2017。我的vsix项目中出现“ mscorlib.dll中的OutOfMemory”异常。 我在此项目中使用Roslyn，下面是查找字段声明和引用的方法。

public static async Task FindFieldDeclarationAndReferencesAsync(string solutionPath, List<Violation> violations) 
{           
    var msWorkspace = MSBuildWorkspace.Create();
    var solution = await msWorkspace.OpenSolutionAsync(solutionPath);***//The solution I am passing to this workspace is 1 GB***
    var documents = solution.Projects.SelectMany(x => x.Documents).ToList();

    foreach (var violation in violations)//violations.Count is approximately 10
    {
        var classFile = documents.Where(x => x.FilePath == violation.FilePath).FirstOrDefault();
        var model = await classFile.GetSemanticModelAsync();
        var root = await classFile.GetSyntaxRootAsync();
        var classDeclarationNode = root.DescendantNodes().OfType<ClassDeclarationSyntax>().Where(x => x.Identifier.Text == violation.ClassName).FirstOrDefault();

        var fieldDeclarationNodeList = classDeclarationNode.DescendantNodes().OfType<FieldDeclarationSyntax>().Where(m => m.Modifiers.ToString().Contains("public const")).SelectMany(x => x.Declaration.Variables.Where(y => y.Identifier.Text == violation.FieldName)).FirstOrDefault();

        ISymbol fieldSymbol = model.GetDeclaredSymbol(fieldDeclarationNodeList);
        var fieldReferences = await SymbolFinder.FindReferencesAsync(fieldSymbol, solution);
        violation.FieldDeclaration = fieldDeclarationNodeList;
        violation.Replacement = Helpers.GetIdentifierReplacement(violation.FieldName);
        violation.References = fieldReferences.SelectMany(item => item.Locations).ToList();
    }               
}

我是否遇到此异常，因为解决方案大小为1 GB，在创建工作区时传递给Roslyn？

异常详细信息：

System.OutOfMemoryException
  HResult=0x8007000E
  Message=Exception of type 'System.OutOfMemoryException' was thrown.
  Source=mscorlib
  StackTrace:
   at System.Threading.ExecutionContext.Capture(StackCrawlMark& stackMark, CaptureOptions options) in f:\dd\ndp\clr\src\BCL\system\threading\executioncontext.cs:line 1281
   at System.Threading.ExecutionContext.FastCapture() in f:\dd\ndp\clr\src\BCL\system\threading\executioncontext.cs:line 1190
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore.GetCompletionAction(Task taskForTracing, MoveNextRunner& runnerToInitialize) in f:\dd\ndp\clr\src\BCL\system\runtime\compilerservices\AsyncMethodBuilder.cs:line 916
   at System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1.AwaitUnsafeOnCompleted[TAwaiter,TStateMachine](TAwaiter& awaiter, TStateMachine& stateMachine) in f:\dd\ndp\clr\src\BCL\system\runtime\compilerservices\AsyncMethodBuilder.cs:line 543
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore.<>c.<ThrowAsync>b__6_1(Object state) in f:\dd\ndp\clr\src\BCL\system\runtime\compilerservices\AsyncMethodBuilder.cs:line 1034
   at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(Object state) in f:\dd\ndp\clr\src\BCL\system\threading\threadpool.cs:line 1273
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) in f:\dd\ndp\clr\src\BCL\system\threading\executioncontext.cs:line 954
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) in f:\dd\ndp\clr\src\BCL\system\threading\executioncontext.cs:line 901
   at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem() in f:\dd\ndp\clr\src\BCL\system\threading\threadpool.cs:line 1250
   at System.Threading.ThreadPoolWorkQueue.Dispatch() in f:\dd\ndp\clr\src\BCL\system\threading\threadpool.cs:line 819
   at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback() in f:\dd\ndp\clr\src\BCL\system\threading\threadpool.cs:line 1161

我在TaskManager中的Handles中检查了我的进程，以下是这些值。

我想摆脱这种例外。 请提出解决方案。

Answer 1

我发现使用Visual Studio“诊断工具”窗口占用更多内存的对象。 在代码的开头和结尾处截取了内存屏幕截图，并比较了两者并解决了该问题。

当violations对象数量很大时， violation.FieldDeclaration和violation.References占用了太多内存。 因此，在每次迭代结束时在finally块中将这些properties to null设置properties to null可以解决此问题。