Xamarin iOS“演练 - 使用Elements API创建应用程序”崩溃

我试图关注Xamarin的“Walkthrough - Creating an application using the Elements API”，当我触摸一个应该启动新屏幕以输入描述的“Task”时，代码崩溃和日期选择器。单击NavigationItem.RightBarButtonItem时会显示任务，但单击其中一个会导致应用程序在模拟器中关闭。Xamarin iOS“演练 - 使用Elements API创建应用程序”崩溃

代码没有太多东西，我也没有看到我出错的地方。

环境：
的Visual Studio 2012> Xamarin构建主机>的Mac OS 10.9.5

整个应用程序中的AppDelegate：

using System; 
using System.Collections.Generic; 
using System.Linq; 

using Foundation; 
using UIKit; 
using MonoTouch.Dialog; 

namespace ElementsApiWalkthrough 
{ 
    public class Task 
    { 
     public Task(){} 

     public string Name { get; set; } 
     public string Description { get; set; } 
     public DateTime DueDate { get; set; } 
    } 

    // The UIApplicationDelegate for the application. This class is responsible for launching the 
    // User Interface of the application, as well as listening (and optionally responding) to 
    // application events from iOS. 
    [Register("AppDelegate")] 
    public partial class AppDelegate : UIApplicationDelegate 
    { 
     // class-level declarations 
     UIWindow _window; 
     RootElement _rootElement; 
     DialogViewController _rootVC; 
     UINavigationController _nav; 
     UIBarButtonItem _addButton; 
     int n; 


     // 
     // This method is invoked when the application has loaded and is ready to run. In this 
     // method you should instantiate the window, load the UI into it and then make the window 
     // visible. 
     // 
     // You have 17 seconds to return from this method, or iOS will terminate your application. 
     // 
     public override bool FinishedLaunching(UIApplication app, NSDictionary options) 
     { 
      _window = new UIWindow(UIScreen.MainScreen.Bounds); 

      _rootElement = new RootElement("To Do List") { new Section() }; 

      // code to create screens with MT.D will go here … 

      _rootVC = new DialogViewController(_rootElement); 
      _nav = new UINavigationController(_rootVC); 
      _window.RootViewController = _nav; 
      _window.MakeKeyAndVisible(); 

      _addButton = new UIBarButtonItem(UIBarButtonSystemItem.Add); 
      _rootVC.NavigationItem.RightBarButtonItem = _addButton; 

      _addButton.Clicked += (sender, e) => 
      { 

       ++n; 

       var task = new Task { Name = "task " + n, DueDate = DateTime.Now }; 

       var taskElement = new RootElement(task.Name){ 
        new Section() { 
          new EntryElement (task.Name, 
            "Enter task description", task.Description) 
        }, 
        new Section() { 
          new DateElement ("Due Date", task.DueDate) 
        } 
       }; 
       _rootElement[0].Add(taskElement); 
      }; 


      return true; 
     } 

    } 
}

来源

2014-09-26 FirstDivision

我已经使用了新的iPhone项目类型。使用“经典”模板中的iPhone项目修复了它。

来源

2014-09-26 20:38:14 FirstDivision

Xamarin iOS“演练 - 使用Elements API创建应用程序”崩溃

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