c# - 呈现 ModalView 时出现 NSInvalidArgumentException

Question

异常消息:

Objective-C exception thrown.  Name: NSInvalidArgumentException Reason: 
Application tried to present a nil modal view controller on target <Navigator: 0x1bed0d0>.

这是我的代码:

    partial void BtnTest (MonoTouch.Foundation.NSObject sender)
    {
        MFMailComposeViewController view = new MFMailComposeViewController();
        view.SetToRecipients(new string[]{"blubb@blubb.de"});
        view.SetMessageBody("Hier steht nun der zusammengestellt text :)", false);
        //view.MailComposeDelegate = new CustomMailComposeDelegate();
        view.SetSubject("Test");

        view.Finished += (s,e)=>
                     {
                            this.NavigationController.DismissModalViewControllerAnimated(true);
        };

        this.BeginInvokeOnMainThread(()=>
        {
            this.NavigationController.PresentModalViewController(view, true);
        });

    }

它适用于 iPad 模拟器，但不适用于设备。

Answer 1

将此声明移到您的方法之外。一旦超出范围，它很可能会立即获得 GC。

MFMailComposeViewController view;