问题描述
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在上次更新（4.0.0）之后，我遇到了一个问题，想知道这是一个错误，并且有修复程序。
从下面的代码中可以看到，我正在创建NavigationItem.RightBarButtonItem并将委托添加到TouchUpInside事件。该按钮已创建，但是当发生触摸时，该应用程序将严重死机（请参阅下文）。在此更新之前，代码运行良好。
有人知道吗？ Monotouch团队，您知道这个问题吗？也许我只是编码不正确并且曾经工作过，但是新的更新证明我编码不正确。
问候，
丹尼
码
//start by creating the view
RectangleF f = new RectangleF(0f,0f,38f,38f);
UIView v = new UIView(f);
//Now create a button with a background
UIButton b = new UIButton(f);
b.SetBackgroundImage(UIImage.FromFile(\"Images/Common/info.png\"),UIControlState.normal);
//add the button to the view
v.Add(b);
b.TouchUpInside
//give teh button a delegate action
b.TouchUpInside += delegate {
//var vc3 = new iPhone_HomeView();
//var vc3 = new iPhone_RetardView();
//vc3.Title = \"asdasd\";
//this.NavigationController.PushViewController (vc3,true);
};
//Now apply the view to the navigation bar on the right
NavigationItem.RightBarButtonItem = new UIBarButtonItem(v);
NavigationItem.RightBarButtonItem.Width = 38f;
0 SmartPhonesolution1 0x000d0db5 mono_handle_native_sigsegv + 343
1 SmartPhonesolution1 0x0000f80c mono_sigsegv_signal_handler + 322
2 libSystem.B.dylib 0x996fb45b _sigtramp + 43
3 ??? 0xffffffff 0x0 + 4294967295
4 UIKit 0x01b92de0 -[UIControl sendAction:to:forEvent:] + 67
5 UIKit 0x01b95262 -[UIControl(Internal) _sendActionsForEvents:withEvent:] + 527
6 UIKit 0x01b93e0f -[UIControl touchesEnded:withEvent:] + 458
7 UIKit 0x01b2b3d0 -[UIWindow _sendtouchesForEvent:] + 567
8 UIKit 0x01b0ccb4 -[UIApplication sendEvent:] + 447
9 UIKit 0x01b119bf _UIApplicationHandleEvent + 7672
10 GraphicsServices 0x05768822 PurpleEventCallback + 1550
11 CoreFoundation 0x00debff4 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 52
12 CoreFoundation 0x00d4c807 __CFRunLoopDoSource1 + 215
13 CoreFoundation 0x00d49a93 __CFRunLoopRun + 979
14 CoreFoundation 0x00d49350 CFRunLoopRunSpecific + 208
15 CoreFoundation 0x00d49271 CFRunLoopRunInMode + 97
16 GraphicsServices 0x0576700c GSEventRunModal + 217
17 GraphicsServices 0x057670d1 GSEventRun + 115
18 UIKit 0x01b15af2 UIApplicationMain + 1160
19 ??? 0x0ba72744 0x0 + 195503940
20 ??? 0x0ba7267a 0x0 + 195503738
21 ??? 0x090bfb9e 0x0 + 151780254
22 ??? 0x090bfaea 0x0 + 151780074
23 ??? 0x090bfb75 0x0 + 151780213
24 SmartPhonesolution1 0x0000f5c7 mono_jit_runtime_invoke + 1332
25 SmartPhonesolution1 0x001ed281 mono_runtime_invoke + 137
26 SmartPhonesolution1 0x001ef968 mono_runtime_exec_main + 669
27 SmartPhonesolution1 0x001eed52 mono_runtime_run_main + 843
28 SmartPhonesolution1 0x000a3153 mono_jit_exec + 200
29 SmartPhonesolution1 0x002a16b8 main + 4155
30 SmartPhonesolution1 0x00002949 _start + 208
31 SmartPhonesolution1 0x00002878 start + 40
解决方法
上周我也遇到了类似的问题。似乎MT 4在GC中比以前的版本更具攻击性，而我以前无法解决的问题现在引起了问题。
尝试在类级别声明UIButton，而不是在本地进行作用域设置。
,移植现有的Objective-C代码时发生了同样的事情。该解决方案是确保您的按钮是类的实例成员。该代码运行良好（省略了额外的ViewController样板代码）：
public partial class HomeViewController : UIViewController
{
private UIButton _settingsButton;
public override void ViewDidLoad()
{
base.ViewDidLoad();
ConfigureNavigationBar();
}
private void ConfigureNavigationBar()
{
// Add the Settings icon to nav bar
_settingsButton = UIButton.FromType(UIButtonType.Custom);
_settingsButton.SetImage(UIImage.FromBundle(\"Images/settings.png\"),UIControlState.Normal);
_settingsButton.SizeToFit();
_settingsButton.TouchUpInside += (sender,e) =>
Console.WriteLine(\"clicked\");
this.NavigationItem.RightBarButtonItem =
new UIBarButtonItem(_settingsButton);
}
}