EXC_BAD_INSTRUCTION按下按鈕

我是Swift的新手，我很努力地學習它，但我遇到了一個謎題。正如你在下面的圖片中看到的那樣，有一些控件正確鏈接到這個視圖控制器，並且在按下UI中的一個按鈕時我們執行下面的代碼，但我總是得到一個EXC_BAD_INSTRUCTION。我不明白爲什麼！EXC_BAD_INSTRUCTION按下按鈕

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這裏是從堆棧跟蹤一些信息。

(lldb) thread info 
thread #1: tid = 0x9319, 0x0006c5d5 App`App.AViewController.sendCommentViaEmail (self=<unavailable>)() ->() + 9349 at AViewController.swift:49, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0) 

(lldb) frame select 1 
frame #1: 0x037067cd libobjc.A.dylib`-[NSObject performSelector:withObject:withObject:] + 84 
libobjc.A.dylib`-[NSObject performSelector:withObject:withObject:] + 84: 
-> 0x37067cd: addl $0x1c, %esp 
    0x37067d0: popl %esi 
    0x37067d1: popl %edi 
    0x37067d2: popl %ebx

編輯：

堆棧跟蹤下面

* thread #1: tid = 0x1e19, 0x0005a5d5 A`A.AViewController.sendCommentViaEmail (self=<unavailable>)() ->() + 9349 at AViewController.swift:49, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0) 
    * frame #0: 0x0005a5d5 A`A.AViewController.sendCommentViaEmail (self=<unavailable>)() ->() + 9349 at AViewController.swift:49 
    frame #1: 0x036f47cd libobjc.A.dylib`-[NSObject performSelector:withObject:withObject:] + 84 
    frame #2: 0x01ea323d UIKit`-[UIApplication sendAction:to:from:forEvent:] + 99 
    frame #3: 0x02213840 UIKit`-[UIBarButtonItem(UIInternal) _sendAction:withEvent:] + 139 
    frame #4: 0x036f47cd libobjc.A.dylib`-[NSObject performSelector:withObject:withObject:] + 84 
    frame #5: 0x01ea323d UIKit`-[UIApplication sendAction:to:from:forEvent:] + 99 
    frame #6: 0x01ea31cf UIKit`-[UIApplication sendAction:toTarget:fromSender:forEvent:] + 64 
    frame #7: 0x01fd6e86 UIKit`-[UIControl sendAction:to:forEvent:] + 69 
    frame #8: 0x01fd72a3 UIKit`-[UIControl _sendActionsForEvents:withEvent:] + 598 
    frame #9: 0x01fd650d UIKit`-[UIControl touchesEnded:withEvent:] + 660 
    frame #10: 0x01ef360a UIKit`-[UIWindow _sendTouchesForEvent:] + 874 
    frame #11: 0x01ef40e5 UIKit`-[UIWindow sendEvent:] + 791 
    frame #12: 0x01eb9549 UIKit`-[UIApplication sendEvent:] + 242 
    frame #13: 0x01ec937e UIKit`_UIApplicationHandleEventFromQueueEvent + 20690 
    frame #14: 0x01e9db19 UIKit`_UIApplicationHandleEventQueue + 2206 
    frame #15: 0x039791df CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15 
    frame #16: 0x0396eced CoreFoundation`__CFRunLoopDoSources0 + 253 
    frame #17: 0x0396e248 CoreFoundation`__CFRunLoopRun + 952 
    frame #18: 0x0396dbcb CoreFoundation`CFRunLoopRunSpecific + 443 
    frame #19: 0x0396d9fb CoreFoundation`CFRunLoopRunInMode + 123 
    frame #20: 0x085dc24f GraphicsServices`GSEventRunModal + 192 
    frame #21: 0x085dc08c GraphicsServices`GSEventRun + 104 
    frame #22: 0x01ea18b6 UIKit`UIApplicationMain + 1526 
    frame #23: 0x000919cc A`main(argc=1, argv=0xbffaa62c) + 76 at main.m:12 
    frame #24: 0x04490ac9 libdyld.dylib`start + 1

下面是我使用的屬性：我得到了相同的結果，他們是否被鏈接到UI與否。

Properties linked to the UI controls and same result