SignalR C# 客户端错误：FormatException：识别的项目之一的格式无效

如何解决SignalR C# 客户端错误：FormatException：识别的项目之一的格式无效

编辑： 这个错误似乎只发生在我的 mac 上。我的朋友在他的 Windows 10 上使用了我的客户端和服务器代码，相同的 Unity3D 版本并且它工作正常。任何想法可能导致此错误？

我有一个使用 SignalR 的 C# 客户端和服务器。服务器运行良好，但客户端在运行 FormatException: One of the identified items was in an invalid format 时总是抛出 StartAsync()。

这是我的代码：

// Client.cs
private void Awake() {
    _Connection = new HubConnectionBuilder()
    .WithUrl("http://localhost:5000/GameHub")
    .ConfigureLogging(logging => {
        logging.SetMinimumLevel(LogLevel.information);
        logging.AddConsole();
    })
    .Build();
}

// called when a button is pressed in Unity
public async void OnClickStartConnection() {
    await _Connection.StartAsync();
}

这是堆栈跟踪：

System.Net.Http.Headers.HttpHeaders.AddInternal (System.String name,System.Collections.Generic.IEnumerable`1[T] values,System.Net.Http.Headers.HeaderInfo headerInfo,System.Boolean ignoreInvalid) (at <efff4cb93af94c0c950db61b78368b54>:0)
System.Net.Http.Headers.HttpHeaders.Add (System.String name,System.Collections.Generic.IEnumerable`1[T] values) (at <efff4cb93af94c0c950db61b78368b54>:0)
System.Net.Http.Headers.HttpHeaders.Add (System.String name,System.String value) (at <efff4cb93af94c0c950db61b78368b54>:0)
Microsoft.AspNetCore.Http.Connections.Client.httpconnection.CreateHttpClient () (at <fc48509a267447ccb7af409e5c632056>:0)
Microsoft.AspNetCore.Http.Connections.Client.httpconnection.set_RemoteEndPoint (System.Net.EndPoint value) (at <fc48509a267447ccb7af409e5c632056>:0)
Microsoft.AspNetCore.Http.Connections.Client.httpconnectionFactory+<ConnectAsync>d__3.MoveNext () (at <fc48509a267447ccb7af409e5c632056>:0)
--- End of stack trace from prevIoUs location where exception was thrown ---
System.Runtime.ExceptionServices.ExceptiondispatchInfo.Throw () (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter`1[TResult].GetResult () (at <695d1cc93cca45069c528c15c9fdd749>:0)
Microsoft.AspNetCore.SignalR.Client.HubConnection+<StartAsyncCore>d__58.MoveNext () (at <ed36b975686d4d58873fbe97ee97567d>:0)
--- End of stack trace from prevIoUs location where exception was thrown ---
System.Runtime.ExceptionServices.ExceptiondispatchInfo.Throw () (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter.GetResult () (at <695d1cc93cca45069c528c15c9fdd749>:0)
Microsoft.AspNetCore.SignalR.Client.HubConnection+<StartAsyncInner>d__50.MoveNext () (at <ed36b975686d4d58873fbe97ee97567d>:0)
--- End of stack trace from prevIoUs location where exception was thrown ---
System.Runtime.ExceptionServices.ExceptiondispatchInfo.Throw () (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter.GetResult () (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Threading.Tasks.ForceAsyncAwaiter.GetResult () (at <ed36b975686d4d58873fbe97ee97567d>:0)
Microsoft.AspNetCore.SignalR.Client.HubConnection+<StartAsync>d__49.MoveNext () (at <ed36b975686d4d58873fbe97ee97567d>:0)
--- End of stack trace from prevIoUs location where exception was thrown ---
System.Runtime.ExceptionServices.ExceptiondispatchInfo.Throw () (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.TaskAwaiter.GetResult () (at <695d1cc93cca45069c528c15c9fdd749>:0)
Client+<OnClickStartConnection>d__2.MoveNext () (at Assets/Scripts/Client.cs:31)
--- End of stack trace from prevIoUs location where exception was thrown ---
System.Runtime.ExceptionServices.ExceptiondispatchInfo.Throw () (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Runtime.CompilerServices.AsyncmethodBuilderCore+<>c.<ThrowAsync>b__6_0 (System.Object state) (at <695d1cc93cca45069c528c15c9fdd749>:0)
UnityEngine.UnitySynchronizationContext+WorkRequest.Invoke () (at /Users/bokken/buildslave/unity/build/Runtime/Export/Scripting/UnitySynchronizationContext.cs:153)
UnityEngine.UnitySynchronizationContext:ExecuteTasks() (at /Users/bokken/buildslave/unity/build/Runtime/Export/Scripting/UnitySynchronizationContext.cs:107)

据我所知，这个问题甚至没有到达服务器。在向 HttpHeaders 添加标头时，查看堆栈跟踪它会出错。我该如何解决这个问题？

环境：

• Mac OS High Sierra
• AspNetCore.SignalR 5.0.7，随 NuGet for Unity 一起安装
• Unity3D 2020.3.11f
• VS Code IDE

解决方法

看起来与https://github.com/dotnet/aspnetcore/issues/30137

相同

Mono 库的头文件有问题，我猜你在 Unity 中使用 Mono。您可以尝试通过定位 netstandard 来解决该问题，或者您可以尝试引用较新版本的 SignalR 客户端，因为该问题已在 6.0.0-preview3 中修复。