Xamarin.Mac模糊标志

Question

我在xamarin.mac中遇到了一个模糊的段错误，这是(无用的)堆栈跟踪：

  at <unknown> <0xffffffff>
  at (wrapper managed-to-native) MonoMac.AppKit.NSApplication.NSApplicationMain     (int,string[]) <0xffffffff>
  at MonoMac.AppKit.NSApplication.Main (string[]) <0x00097>
  at gitbookpro.mac.MainClass.Main (string[]) <0x00017>
  at (wrapper runtime-invoke) <Module>.runtime_invoke_void_object (object,intptr,intptr,intptr) <0xffffffff>

在处理NSOutlineView上的SelectionDidChange后发生崩溃，这会进行相当多的处理。

很难确定到底是什么导致了这次崩溃。

有什么想法吗？

Answer 1

该错误是由于，C#对象被错误地清理了收集的而导致的。

它们被垃圾收集，因为这些对象被返回到objective-c代码(本机代码)，并且由于C#中没有保留引用，垃圾收集器将删除它们。

这就是发生的事情：

1. create C# obj 2. return obj to native code 3. ... wait a little bit ... 4. turn native object back into to C# obj (in event handlers etc ...) 5. Access C# obj <= This would fail occasionally since it was being garbage collected during step #3

你应该做的是：

1. create C# obj 1bis. Keep an extra reference to the object somewhere (in an Dictionary for example) 2. return obj to native code 3. ... wait a little bit ... 4. turn native object back into to C# obj (in event handlers etc ...) 4bis. Remove extra reference 5. Access C# obj <= This would fail occasionally since it was being garbage collected during step #3

就是这样！