Xamarin.Mac事件和線程似乎不能一起工作

Question

我在Xamarin.Mac目前有很多困難。

基本上我想要做的就是POST和從Web服務器獲取一些JSON，然後調用一個事件，它通過委託向（最終會是一個）UI變化事件（目前它只是一個debug.writeline調用）。我有兩個PCL庫，一個是'核心'，另一個是庫核心參考，一個WPF應用程序和一個OS X應用程序 - WPF應用程序工作正常。我也使用MVVMCross。

起初，我嘗試使用我已經使用HTTPWebRequest的預先存在的類，並且它工作正常，第一次按鈕單擊（它觸發此調用）。在第二個按鈕上單擊OS X應用程序崩潰。我嘗試切換到HttpClient，沒有骰子。

看完此線程：https://bugzilla.xamarin.com/show_bug.cgi?id=19906我嘗試過，使用接口將OS X應用程序的HTTP類轉換爲NSUrlConnection的本地實現。

現在，這是我發現自己的situaiton： 如果我有傳遞給它一個匿名函數NSURLConnection的異步請求，如果我採取了它的工作原理永遠點擊 後單擊並調用FireEvent（）函數，它只是提高事件（這可能會引發更多的事件）然後它永遠有效，單擊後點擊 如果我同時使用匿名函數和FireEvent，在第三次點擊按鈕時，它會拋出本地崩潰。

如果我拿出所有的異步的東西，它會正常工作，但這並不理想。

任何想法？我在我的智慧結束。

 public void ExecuteAsync() 
    { 
     var request = new NSUrlRequest(new NSUrl("http://www.example.com")); 

     asyncRunning = true; 

     NSUrlConnection.SendAsynchronousRequest(request, NSOperationQueue.MainQueue, delegate(NSUrlResponse response, NSData data, NSError error) { 

     var responseStr = data.ToString(); 

      var blah = new HttpResponseCompleteEventArgs("{TESTJSONThatIveRemovedForReadability}"); 

      System.Diagnostics.Debug.WriteLine("Inside IsMainThread: " + NSThread.IsMain.ToString()); 

      response.InvokeOnMainThread (delegate { 
       FireEvent(blah); 
       System.Diagnostics.Debug.WriteLine("Inside IsMainThread invoke: " + NSThread.IsMain.ToString()); 
      }); 



     }); 

     System.Diagnostics.Debug.WriteLine("Outside IsMainThread: " + NSThread.IsMain.ToString()); 


    } 

和碰撞吸能

Stacktrace: 

    at <unknown> <0xffffffff> 
    at (wrapper managed-to-native) MonoMac.AppKit.NSApplication.NSApplicationMain (int,string[]) <IL 0x0009d, 0xffffffff> 
    at MonoMac.AppKit.NSApplication.Main (string[]) [0x00041] in /Users/builder/data/lanes/xamcore-lion-1.8-branch/b8b75fd4/source/xamcore/src/AppKit/NSApplication.cs:105 
    at FreshlySqueezed.Mac.MainClass.Main (string[]) [0x00007] in /Users/blah/Development/Development/FreshlySqueezed/FreshlySqueezed.Mac/Main.cs:14 
    at (wrapper runtime-invoke) <Module>.runtime_invoke_void_object (object,intptr,intptr,intptr) <IL 0x00050, 0xffffffff> 

Native stacktrace: 


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quProcess 2693 stopped 
* thread #1: tid = 0x1e2f7, 0x91b0cfed libsystem_kernel.dylib`__wait4 + 5, queue = 'com.apple.main-thread', stop reason = signal SIGSTOP 
    thread #2: tid = 0x1e30e, 0x91b0d992 libsystem_kernel.dylib`kevent64 + 10, queue = 'com.apple.libdispatch-manager' 
    thread #3: tid = 0x1e30f, 0x91b0d046 libsystem_kernel.dylib`__workq_kernreturn + 10 
    thread #4: tid = 0x1e310, 0x91b0d046 libsystem_kernel.dylib`__workq_kernreturn + 10 
    thread #5: tid = 0x1e311, 0x91b0d046 libsystem_kernel.dylib`__workq_kernreturn + 10 
    thread #6: tid = 0x1e314, 0x91b07fb6 libsystem_kernel.dylib`semaphore_wait_trap + 10 
    thread #7: tid = 0x1e315, 0x91b0ca26 libsystem_kernel.dylib`__recvfrom + 10 
    thread #8: tid = 0x1e32c, 0x91b07f7a libsystem_kernel.dylib`mach_msg_trap + 10 
    thread #9: tid = 0x1e32e, 0x91b0d046 libsystem_kernel.dylib`__workq_kernreturn + 10 
(lldb) quit 

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qu* thread #1: tid = 0x1e2f7, 0x91b0cfed libsystem_kernel.dylib`__wait4 + 5, queue = 'com.apple.main-thread', stop reason = signal SIGSTOP 
    * frame #0: 0x91b0cfed libsystem_kernel.dylib`__wait4 + 5 
    frame #1: 0x92c46ec5 libsystem_c.dylib`waitpid$UNIX2003 + 48 
    frame #2: 0x018ab5f9 libmono-2.0.dylib`mono_handle_native_sigsegv(signal=11, ctx=0x006e1fe0) + 489 at mini-exceptions.c:2305 
    frame #3: 0x018fd9d5 libmono-2.0.dylib`mono_arch_handle_altstack_exception(sigctx=0x006e1fe0, fault_addr=0x608962a8, stack_ovf=0) + 149 at exceptions-x86.c:1170 
    frame #4: 0x01804351 libmono-2.0.dylib`mono_sigsegv_signal_handler(_dummy=11, info=0x006e1fa0, context=0x006e1fe0) + 369 at mini.c:6842 
    frame #5: 0x94fd1deb libsystem_platform.dylib`_sigtramp + 43 

    thread #2: tid = 0x1e30e, 0x91b0d992 libsystem_kernel.dylib`kevent64 + 10, queue = 'com.apple.libdispatch-manager' 
    frame #0: 0x91b0d992 libsystem_kernel.dylib`kevent64 + 10 
    frame #1: 0x9a415899 libdispatch.dylib`_dispatch_mgr_invoke + 238 
    frame #2: 0x9a415532 libdispatch.dylib`_dispatch_mgr_thread + 52 

    thread #3: tid = 0x1e30f, 0x91b0d046 libsystem_kernel.dylib`__workq_kernreturn + 10 
    frame #0: 0x91b0d046 libsystem_kernel.dylib`__workq_kernreturn + 10 
    frame #1: 0x91cfbdcf libsystem_pthread.dylib`_pthread_wqthread + 372 

    thread #4: tid = 0x1e310, 0x91b0d046 libsystem_kernel.dylib`__workq_kernreturn + 10 
    frame #0: 0x91b0d046 libsystem_kernel.dylib`__workq_kernreturn + 10 
    frame #1: 0x91cfbdcf libsystem_pthread.dylib`_pthread_wqthread + 372 

    thread #5: tid = 0x1e311, 0x91b0d046 libsystem_kernel.dylib`__workq_kernreturn + 10 
    frame #0: 0x91b0d046 libsystem_kernel.dylib`__workq_kernreturn + 10 
    frame #1: 0x91cfbdcf libsystem_pthread.dylib`_pthread_wqthread + 372 

    thread #6: tid = 0x1e314, 0x91b07fb6 libsystem_kernel.dylib`semaphore_wait_trap + 10 
    frame #0: 0x91b07fb6 libsystem_kernel.dylib`semaphore_wait_trap + 10 
    frame #1: 0x01a1891e libmono-2.0.dylib`mono_sem_wait(sem=<unavailable>, alertable=<unavailable>, sem=0x01b1ac20, alertable=1) + 30 at mono-semaphore.c:121 
    frame #2: 0x019c43ea libmono-2.0.dylib`finalizer_thread(unused=0x00000000) + 74 at gc.c:1073 
    frame #3: 0x0199c654 libmono-2.0.dylib`start_wrapper [inlined] start_wrapper_internal(data=0x00193bd0) + 442 at threads.c:647 
    frame #4: 0x0199c49a libmono-2.0.dylib`start_wrapper(data=0x00193bd0) + 26 at threads.c:692 
    frame #5: 0x01a1de1d libmono-2.0.dylib`inner_start_thread(arg=0xbffff2c0) + 253 at mono-threads-posix.c:94 
    frame #6: 0x01a3eebd libmono-2.0.dylib`GC_start_routine(arg=0x006e2f60) + 93 at pthread_support.c:1502 
    frame #7: 0x91cfa5fb libsystem_pthread.dylib`_pthread_body + 144 
    frame #8: 0x91cfa485 libsystem_pthread.dylib`_pthread_start + 130 

    thread #7: tid = 0x1e315, 0x91b0ca26 libsystem_kernel.dylib`__recvfrom + 10 
    frame #0: 0x91b0ca26 libsystem_kernel.dylib`__recvfrom + 10 
    frame #1: 0x92c470c9 libsystem_c.dylib`recv$UNIX2003 + 54 
    frame #2: 0x018d58c0 libmono-2.0.dylib`socket_transport_recv(buf=0xb039aeed, len=11) + 160 at debugger-agent.c:1085 
    frame #3: 0x018d1c8d libmono-2.0.dylib`debugger_thread(arg=0x00000000) + 21485 at debugger-agent.c:1475 
    frame #4: 0x01a1de1d libmono-2.0.dylib`inner_start_thread(arg=0xbffff2c0) + 253 at mono-threads-posix.c:94 
    frame #5: 0x01a3eebd libmono-2.0.dylib`GC_start_routine(arg=0x006e2f60) + 93 at pthread_support.c:1502 
    frame #6: 0x91cfa5fb libsystem_pthread.dylib`_pthread_body + 144 
    frame #7: 0x91cfa485 libsystem_pthread.dylib`_pthread_start + 130 

    thread #8: tid = 0x1e32c, 0x91b07f7a libsystem_kernel.dylib`mach_msg_trap + 10 
    frame #0: 0x91b07f7a libsystem_kernel.dylib`mach_msg_trap + 10 
    frame #1: 0x91b0716c libsystem_kernel.dylib`mach_msg + 68 
    frame #2: 0x9bea0bf9 CoreFoundation`__CFRunLoopServiceMachPort + 169 
    frame #3: 0x9bea01d1 CoreFoundation`__CFRunLoopRun + 1393 
    frame #4: 0x9be9f9ea CoreFoundation`CFRunLoopRunSpecific + 394 
    frame #5: 0x9be9f84b CoreFoundation`CFRunLoopRunInMode + 123 
    frame #6: 0x90de9b88 AppKit`_NSEventThread + 283 
    frame #7: 0x91cfa5fb libsystem_pthread.dylib`_pthread_body + 144 
    frame #8: 0x91cfa485 libsystem_pthread.dylib`_pthread_start + 130 

    thread #9: tid = 0x1e32e, 0x91b0d046 libsystem_kernel.dylib`__workq_kernreturn + 10 
    frame #0: 0x91b0d046 libsystem_kernel.dylib`__workq_kernreturn + 10 
    frame #1: 0x91cfbdcf libsystem_pthread.dylib`_pthread_wqthread + 372 
Executing commands in '/tmp/mono-gdb-commands.J45EfM'. 
(lldb) process attach --pid 2693 
Process 2693 stopped 

任何人有什麼想法？我很難過。

感謝

Answer 1

所以撓頭了幾個小時之後我似乎已經在整個解決方案絆倒了。

從早期我就懷疑這與垃圾收集有關，或者在第三次點擊按鈕之後碰到任何代碼之前應用程序崩潰，並且從閱讀其他堆棧溢出Xamarin/OS X的問題，我的症狀聽起來很像一個過分渴望的垃圾收集器。

所以起初我以爲每次我從Web服務器獲得響應時都會引發一個事件，並且事件已經冒泡到ViewModel，所以本質上是將其冒泡給OSX項目中的ViewController。其目的是嘗試使用此事件重新綁定每次點擊後的按鈕綁定 - 但我試着用空的事件處理程序運行它，並且我發現它修復了最初的問題！

儘管事實上ViewController已經通過this.ViewModel引用了ViewModel，但看起來OS X/XamMac正在過度渴望和處置ViewModel，因此將App引入了它的膝蓋。有趣的是，我只發現添加和處理一個事件來解決這個問題，試圖將this.ViewModel分配給另一個類變量沒有效果。

所以這裏的是固定它的代碼：

在我加入這個視圖模型：

public event System.EventHandler GoCommandFinished; 

public void CallbackFromWebRequest(SqueezeBase value){ 
       System.Diagnostics.Debug.WriteLine("hmmm"); 
      Hello = "whey?" + x; 
      if (GoCommandFinished != null) { 
       GoCommandFinished (null, null); 
      } 
     } 

，並在Mac OS X的身邊，我已將此添加到viewDidLoad中的視圖控制器：

((FirstViewModel)this.ViewModel).GoCommandFinished += GoCommandFinished; 

然後創建一個空函數來處理這個問題：

private void GoCommandFinished(object sender, EventArgs e){ 

     } 

和volia！我有興趣知道一個更清晰的方法來整理這件事，因爲這對我來說非常難以理解......但現在，我不在乎，它的工作原理！但是如果Xamarin的任何人都能解釋如何更加優雅地冷靜垃圾收集，那會很棒！

謝謝