c# - Crash when creating MenuItem in code (MonoMac) -

i trying add menu items submenu dynamically during runtime. can add nsmenuitem fine , shows up. if try add event handler, either directly argument constructor, or assigning activated event, crash. menu , submenu created in xcode. add/remove items in 1 specific submenu during runtime.

the crash occurs when submenu drawn. right-click, move mouse on context menu until come item under dynamic submenu resides, , crash!

the crash report quite long here's part think relevant:

thread 1 (process 6706): #0  0x94f73095 in __wait4 () #1  0x9928699a in waitpid$unix2003 () #2  0x004a7d22 in mono_handle_native_sigsegv (signal=11, ctx=0xf6fe0) @ mini-exceptions.c:2344 #3  0x004f7645 in mono_arch_handle_altstack_exception (sigctx=0xf6fe0, fault_addr=0xc8080824, stack_ovf=0) @ exceptions-x86.c:1135 #4  0x00404061 in mono_sigsegv_signal_handler (_dummy=11, info=0xf6fa0, context=0xf6fe0) @ mini.c:6556 #5  <signal handler called> #6  0x98a83a8b in objc_msgsend () #7  0xbfffd920 in ?? () #8  0x9730c963 in -[nscarbonmenuimpl _carbonupdatestatusevent:handlercallref:] () #9  0x973086ee in nsslmmenueventhandler () #10 0x908f79bb in _invokeeventhandlerupp () #11 0x9077f394 in dispatcheventtohandlers () #12 0x9077e780 in sendeventtoeventtargetinternal () #13 0x90792655 in sendeventtoeventtarget () #14 0x908f786a in sendhicommandevent () #15 0x907535f0 in updatehicommandstatuswithcachedevent () #16 0x9077abe2 in hiapplication::eventhandler () #17 0x908f79bb in _invokeeventhandlerupp () #18 0x9077f394 in dispatcheventtohandlers () #19 0x9077e780 in sendeventtoeventtargetinternal () #20 0x90792655 in sendeventtoeventtarget () #21 0x90943054 in sendmenuopening () #22 0x90752dfd in drawthemenu () #23 0x90945779 in opensubmenu () #24 0x90752427 in trackmenucommon () #25 0x9094490d in popupmenuselectcore () #26 0x909441e2 in _handlepopupmenuselection7 () #27 0x97398295 in _nsslmpopupcarbonmenu3 () #28 0x973971b1 in -[nscarbonmenuimpl _popupcontextmenu:withevent:forview:withfont:] () #29 0x97515063 in -[nsmenu _popupcontextmenu:withevent:forview:withfont:] () #30 0x97514f56 in -[nsmenu _popupcontextmenu:withevent:forview:] () #31 0x97515390 in -[nsmenu _popupmenuwithevent:forview:] () #32 0x9771af45 in -[nsview rightmousedown:] () #33 0x973ed635 in -[nscontrol _rightmouseupordown:] () #34 0x973ed69f in -[nscontrol rightmousedown:] () #35 0x971c8af1 in -[nswindow sendevent:] () #36 0x971c390f in -[nsapplication sendevent:] () #37 0x970dd62c in -[nsapplication run] () #38 0x970805f6 in nsapplicationmain () #39 0x06de146b in ?? () #40 0x06de1290 in ?? () #41 0x000befe4 in ?? () #42 0x000bf12f in ?? () #43 0x0040dc05 in mono_jit_runtime_invoke (method=0x9e8c1c, obj=0x0, params=0xbffff468, exc=0x0) @ mini.c:6438 #44 0x005c49ae in mono_runtime_invoke (method=0x9e8c1c, obj=0x0, params=0xbffff468, exc=0x0) @ object.c:2827 #45 0x005c8dc4 in mono_runtime_exec_main (method=0x9e8c1c, args=0xe7f30, exc=0x0) @ object.c:4054 #46 0x005c9135 in mono_runtime_run_main (method=0x9e8c1c, argc=0, argv=0x168d18, exc=0x0) @ object.c:3678 #47 0x00478685 in mono_jit_exec (domain=0x94e00, assembly=0x1833b0, argc=2, argv=0x168d18) @ driver.c:955 #48 0x0047abbf in mono_main (argc=4, argv=0x168d10) @ driver.c:1014 #49 0x0000308f in main () 

i running xamarin studio 4.0.12, mono 3.2.0, xcode 4.6.3, xamarin.mac 1.4.8, os x 10.8.4

i'm hoping our experience shed light. although without code it's rather difficult.

xamarin.mac fantastic job abstracting stuff c# types. 1 thing can't avoided different way each os (and windowing systems in particular) time painting events , resource retention.

in particular cocoa controller style of windowing, there's far greater risk of items expected referenced in memory have been cleaned up, cocoa seems far happier switching windows/controllers , re-hydrating again.

tl;dr

1. keep modular reference menuitems - store them in field on controller. otherwise collected.
2. before performing repainting, ensure you've no circular references (with cocoa's habit of defining behaviour in delegates belonging objects easier windows)
3. removing menu items must end start (remember counts reduce remove)

we have found such mysterious crashes due disappearing controls , or delegates referring objects have reference delegate.

i'm sure more code can more!

cheers ian