无法使用 iOS 中的情节提要使 MvvmCross 工作答案

【问题标题】：Cannot get MvvmCross using storyboards in iOS to work无法使用 iOS 中的情节提要使 MvvmCross 工作
【发布时间】：2015-01-28 18:40:22
【问题描述】：

我正在尝试使用 StoryBoards 编写 MvvmCross 应用程序。我知道有类似的问题，但我遵循了解决方案，但我无法让它发挥作用。我已经引用了我在这个问题中尝试过的解决方案之一。

我将从一开始就解释我做了什么，希望这将有助于诊断我的问题

在 Visual Studio 中使用通用 iOS 单一视图应用创建项目。
我执行标准的 MvvmCross 设置、添加 nuget、更新 AppDelegate 等。
我可以编译它。
我向 iPhone 故事板添加了一个新的 ViewController。我称之为LogonViewController。我将 Class、Storyboard ID 和 Restoration ID 设置为 LogonViewController。生成 LogonViewController 类。我将其更改为从 MvxViewController 派生
我将入口箭头从 RootViewController（最初创建时故事板上的视图控制器）移到 LogonViewController。我将 RootViewController 留在情节提要上
我将 LogonViewController 类更改为从 MvxViewController 派生，并将 Register 属性设置为 LogonView，例如
```
[Register ("LogonView")]
partial class LogonViewController
```
我向 LogonViewController 添加了一个标签，作为要显示的内容。
我根据

MVVMCross support for Xamarin.iOS Storyboards

问题是当在自定义容器中调用被覆盖的方法（如下所示）时，我得到一个无效的转换异常，因为它无法将 UIKit.UIViewController 转换为 IMvxTouchView

我也遇到算术溢出异常

protected override IMvxTouchView CreateViewOfType(Type viewType, MvxViewModelRequest request)
{
    return (IMvxTouchView)UIStoryboard.FromName("MyStoryBoard", null)


    .InstantiateViewController(viewType.Name);
}

在跟踪日志中我收到以下错误

2015-01-28 18:12:09.833 MyApp[3743:68927] mvx:Diagnostic:  8.61 Setup: LastChance start
[0:] mvx:Diagnostic:  8.61 Setup: LastChance start
[0:] 
2015-01-28 18:12:10.247 MyApp[3743:68927] mvx:Diagnostic:  9.05 Setup: Secondary end
[0:] mvx:Diagnostic:  9.05 Setup: Secondary end
[0:] 
2015-01-28 18:12:10.647 MyApp[3743:68927] mvx:Diagnostic:  9.43 Showing ViewModel LogonViewModel
[0:] mvx:Diagnostic:  9.43 Showing ViewModel LogonViewModel
[0:] 
2015-01-28 18:12:11.049 MyApp[3743:68927] TouchNavigation:Diagnostic:  9.83 Navigate requested
[0:] TouchNavigation:Diagnostic:  9.83 Navigate requested
2015-01-28 18:12:11.254 MyApp[3743:68927] Unknown class LogonViewController in Interface Builder file.
2015-01-28 18:12:23.962 MyApp[3743:68927] -[UIViewController bottomLayoutGuide]: guide not available before the view controller's view is loaded
System.OverflowException: Arithmetic operation resulted in an overflow.
   at Mono.Debugging.Soft.SoftDebuggerAdaptor.TargetObjectToObject(EvaluationContext ctx, Object obj)
   at Mono.Debugging.Evaluation.ExpressionEvaluator.TargetObjectToExpression(EvaluationContext ctx, Object obj)
   at Mono.Debugging.Evaluation.ObjectValueAdaptor.CreateObjectValueImpl(EvaluationContext ctx, IObjectValueSource source, ObjectPath path, Object obj, ObjectValueFlags flags)
   at Mono.Debugging.Evaluation.ObjectValueAdaptor.CreateObjectValue(EvaluationContext ctx, IObjectValueSource source, ObjectPath path, Object obj, ObjectValueFlags flags)
System.OverflowException: Arithmetic operation resulted in an overflow.
   at Mono.Debugging.Soft.SoftDebuggerAdaptor.TargetObjectToObject(EvaluationContext ctx, Object obj)
   at Mono.Debugging.Evaluation.ExpressionEvaluator.TargetObjectToExpression(EvaluationContext ctx, Object obj)
   at Mono.Debugging.Evaluation.ObjectValueAdaptor.CreateObjectValueImpl(EvaluationContext ctx, IObjectValueSource source, ObjectPath path, Object obj, ObjectValueFlags flags)
   at Mono.Debugging.Evaluation.ObjectValueAdaptor.CreateObjectValue(EvaluationContext ctx, IObjectValueSource source, ObjectPath path, Object obj, ObjectValueFlags flags)
System.OverflowException: Arithmetic operation resulted in an overflow.
   at Mono.Debugging.Soft.SoftDebuggerAdaptor.TargetObjectToObject(EvaluationContext ctx, Object obj)
   at Mono.Debugging.Evaluation.ExpressionEvaluator.TargetObjectToExpression(EvaluationContext ctx, Object obj)
   at Mono.Debugging.Evaluation.ObjectValueAdaptor.CreateObjectValueImpl(EvaluationContext ctx, IObjectValueSource source, ObjectPath path, Object obj, ObjectValueFlags flags)
   at Mono.Debugging.Evaluation.ObjectValueAdaptor.CreateObjectValue(EvaluationContext ctx, IObjectValueSource source, ObjectPath path, Object obj, ObjectValueFlags flags)
Unhandled Exception:

System.InvalidCastException: Unable to cast object of type 'UIKit.UIViewController' to type 'Cirrious.MvvmCross.Touch.Views.IMvxTouchView'.

我不知道我在这里做错了什么。有没有人有任何想法？这是安装的软件版本

MvvmCross 3.5.0 Visual Studio 2012 更新 4， Xamarin 通用安装程序 v3.5.0.0 Xamarin Studio 5.7 v5.7.0.661 Xamarin v3.9.236.0

更新

我接受了 EShy 的建议并添加了控制器并将其命名为 LogonView，但是我仍然遇到 LogonViewModel 未构建的问题。日志如下所示。有什么想法吗？

2015-01-29 11:31:33.579 MyApp[12631:273902] mvx:Diagnostic:286.77 Message = [Failed to construct and initialize ViewModel for type MyApp.Core.ViewModels.LogonViewModel from locator MvxDefaultViewModelLocator - check InnerException for more information]
[0:] mvx:Diagnostic:286.77 Message = [Failed to construct and initialize ViewModel for type MyApp.Core.ViewModels.LogonViewModel from locator MvxDefaultViewModelLocator - check InnerException for more information]
[0:] 
2015-01-29 11:31:33.985 MyApp[12631:273902] mvx:Diagnostic:287.17 Stack Trace = [  at Cirrious.MvvmCross.ViewModels.MvxViewModelLoader.LoadViewModel (Cirrious.MvvmCross.ViewModels.MvxViewModelRequest request, IMvxBundle savedState, IMvxViewModelLocator viewModelLocator) [0x00000] in <filename unknown>:0 
  at Cirrious.MvvmCross.ViewModels.MvxViewModelLoader.LoadViewModel (Cirrious.MvvmCross.ViewModels.MvxViewModelRequest request, IMvxBundle savedState) [0x00000] in <filename unknown>:0 
  at Cirrious.MvvmCross.Touch.Views.MvxViewControllerExtensionMethods.LoadViewModel (IMvxTouchView touchView) [0x00000] in <filename unknown>:0 
  at Cirrious.MvvmCross.Views.MvxViewExtensionMethods.OnViewCreate (IMvxView view, System.Func`1 viewModelLoader) [0x00000] in <filename unknown>:0 
  at Cirrious.MvvmCross.Touch.Views.MvxViewControllerExtensionMethods.OnViewCreate (IMvxTouchView touchView) [0x00000] in <filename unknown>:0 
  at Cirrious.MvvmCross.Touch.Views.MvxViewControllerAdapter.HandleViewDidLoadCalled 
[0:] mvx:Diagnostic:287.17 Stack Trace = [  at Cirrious.MvvmCross.ViewModels.MvxViewModelLoader.LoadViewModel (Cirrious.MvvmCross.ViewModels.MvxViewModelRequest request, IMvxBundle savedState, IMvxViewModelLocator viewModelLocator) [0x00000] in <filename unknown>:0 
  at Cirrious.MvvmCross.ViewModels.MvxViewModelLoader.LoadViewModel (Cirrious.MvvmCross.ViewModels.MvxViewModelRequest request, IMvxBundle savedState) [0x00000] in <filename unknown>:0 
  at Cirrious.MvvmCross.Touch.Views.MvxViewControllerExtensionMethods.LoadViewModel (IMvxTouchView touchView) [0x00000] in <filename unknown>:0 
  at Cirrious.MvvmCross.Views.MvxViewExtensionMethods.OnViewCreate (IMvxView view, System.Func`1 viewModelLoader) [0x00000] in <filename unknown>:0 
  at Cirrious.MvvmCross.Touch.Views.MvxViewControllerExtensionMethods.OnViewCreate (IMvxTouchView touchView) [0x00000] in <filename unknown>:0 
  at Cirrious.MvvmCross.Touch.Views.MvxViewControllerAdapter.HandleViewDidLoadCalled (System.Object sender, System.EventArgs e) [0x00000] in <filename unknown>:0 
  at (wrapper delegate-invoke) <Module>:invoke_void_object_EventArgs (object,System.EventArgs)
  at Cirrious.CrossCore.Core.MvxDelegateExtensionMethods.Raise (System.EventHandler eventHandler, System.Object sender) [0x00000] in <filename unknown>:0 
  at Cirrious.CrossCore.Touch.Views.MvxEventSourceViewController.ViewDidLoad () [0x00000] in <filename unknown>:0 
  at (wrapper managed-to-native) UIKit.UIApplication:UIApplicationMain (int,string[],intptr,intptr)
  at UIKit.UIApplication.Main (System.String[] args, IntPtr principal, IntPtr delegate) [0x00005] in /Developer/MonoTouch/Source/monotouch/src/UIKit/UIApplication.cs:62 
  at UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x00038] in /Developer/MonoTouch/Source/monotouch/src/UIKit/UIApplication.cs:46 
  at MyApp.iOS.Application.Main (System.String[] args) [0x00002] in c:\MyApp.iOS\Main.cs:21 ]
(System.Object sender, System.EventArgs e) [0x00000] in <filename unknown>:0 
  at (wrapper delegate-invoke) <Module>:invoke_void_object_EventArgs (object,System.EventArgs)
  at Cirrious.CrossCore.Core.MvxDelegateExtensionMethods.Raise (System.EventHandler eventHandler, System.Object sender) [0x00000] in <filename unknown>:0 
  at Cirrious.CrossCore.Touch.Views.MvxEventSourceViewController.ViewDidLoad () [0x00000] in <filename unknown>:0 
  at (wrapper managed-to-native) UIKit.UIApplication:UIApplicationMain (int,string[],intptr,intptr)
  at UIKit.UIApplication.Main (System.String[] args, IntPtr principal, IntPtr delegate) [0x00005] in /Developer/MonoTouch/Source/monotouch/src/UIKit/UIApplication.cs:62 
  at UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x00038] in /Developer/MonoTouch/Source/monotouch/src/UIKit/UIApplication.cs:46 
  at MyApp.iOS.Application.Main (System.String[] args) [0x00002] in c:\MyApp\
MyApp.iOS\Main.cs:21 ]
[0:] 
2015-01-29 11:31:34.393 MyApp[12631:273902] mvx:Diagnostic:287.58 Inner Exception message = [Problem creating viewModel of type LogonViewModel]
[0:] mvx:Diagnostic:287.58 Inner Exception message = [Problem creating viewModel of type LogonViewModel]

【问题讨论】：

如果将UIStoryboard.FromName("MyStoryBoard", null).InstantiateViewController(viewType.Name);返回的ref存储在一个变量中，然后使用监视窗口，返回的是什么类型的控制器？
我会做那个斯图尔特，可能需要一段时间，有一些问题。我是否还必须将我正在使用的情节提要添加到项目设置中？
嗨 Stuart，我按照 EShy 的建议做了，并在情节提要中添加了一个视图控制器，并将其命名为 LogonView 而不是 LogonViewController。返回的类型现在是 MvxViewController。但是我仍然遇到异常，它无法构造 LogonViewModel。我已将其作为更新添加到原始问题中
我看到是错误Unknown class LogonViewController in Interface Builder file - 先尝试解决该错误？
嗨 Stuart，自从我将 ViewController 设置为 LogonView 后，该错误已经消失。现在的问题是无法创建 LogonViewModel。我已经在问题上添加了日志，所以阅读起来更清晰

标签： ios xamarin storyboard mvvmcross

【解决方案1】：

您应该在情节提要 LogonView 中命名您的视图控制器，而不是 LogonViewController。这就是 MvvmCross 正在寻找的 viewType.Name。

【讨论】：

我明天试试看能否解决问题。感谢您的帮助

【解决方案2】：

问题在于注入 LogonViewModel 的服务使用了 MvvmCross Messenger 插件。我没有通过 nuget 将插件添加到项目中。通知我这一点的异常是内部异常的内部异常。我应该挖得更深。再次感谢 Stuart 的帮助和 MvvmCross 的整体优势。还要感谢 EShy 的命名帮助。

【讨论】：