Catel 与 Xamarin.Forms

Question

我无法让 Xamarin.Forms 和 Catel 一起工作。

我看到了这个sample，但它似乎已经过时了。

当我通过 NuGet 下载 Catel 时，我遇到不同版本的不同问题：

• v5.1：

  编译时异常：

  Exception while loading assemblies: System.IO.FileNotFoundException: Could not load assembly 'Obsolete, Version=4.2.4.0, Culture=neutral, PublicKeyToken=1ca091877d12ca03'. Perhaps it doesn't exist in the Mono for Android profile?

• v5.0：

  运行时异常（创建new App();时）：

  Could not load signature of Catel.MVVM.IViewModelFactory:CreateViewModel due to: Could not resolve type with token 01000061 (from typeref, class/assembly System.ComponentModel.IDataErrorInfo, Catel.Core, Version=5.0.0.0, Culture=neutral, PublicKeyToken=null) assembly:Catel.Core, Version=5.0.0.0, Culture=neutral, PublicKeyToken=null type:System.ComponentModel.IDataErrorInfo member:<none>

• v4.5.*

  • 使用ViewModelBase：

    创建应用程序对象时的运行时异常： System.TypeLoadException：无法使用令牌解析类型 01000097（来自 typeref、类/程序集 System.Reflection.BindingFlags、Catel.Core、Version=4.5.4.0、Culture=neutral、PublicKeyToken=null）

  • 我对@9​​87654326@的实现：

    好的，MainPage 加载，绑定工作，构造函数通过参数获得正确的服务，但是，例如，当我调用 '_uiVisualizerService.Show(subPageViewModel);'从命令，它抛出'InvalidCastException'。异常前 Catel 日志中的最后一行：Injecting properties into type 'SubPage' after construction。但是 SubPage 和 SubPageViewModel 绝对是空的。

    详情：

    ---> System.InvalidCastException: Specified cast is not valid. at Catel.Services.UIVisualizerService+<ShowAsync>d__9.MoveNext () [0x00096] in C:\CI_WS\Ws\97969\Source\Catel\src\Catel.MVVM\Catel.MVVM.Xamarin.Forms\Services\UIVisualizerService.cs:151 at System.Threading.Tasks.Task.ThrowIfExceptional (System.Boolean includeTaskCanceledExceptions) [0x00011] in <183b200ee49746d48fc781625979428e>:0 at System.Threading.Tasks.Task'1[TResult].GetResultCore (System.Boolean waitCompletionNotification) [0x0002b] in <183b200ee49746d48fc781625979428e>:0 at System.Threading.Tasks.Task'1[TResult].get_Result () [0x0000f] in <183b200ee49746d48fc781625979428e>:0 at Catel.Services.UIVisualizerService.Show (Catel.MVVM.IViewModel viewModel, System.EventHandler``1[TEventArgs] completedProc) [0x00000] in C:\CI_WS\Ws\97969\Source\Catel\src\Catel.MVVM\Catel.MVVM.Xamarin.Forms\Services\UIVisualizerService.cs:125 at XamarinFormsCatel.ViewModels.MainPageViewModel.OnGo () [0x00015] in C:\!Work\Test\XamarinFormsCatel\XamarinFormsCatel\XamarinFormsCatel\XamarinFormsCatel\ViewModels\MainPageViewModel.cs:34 at Xamarin.Forms.Command+<>c__DisplayClass3_0.<.ctor>b__0 (System.Object o) [0x00000] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Core\Command.cs:73 at Xamarin.Forms.Command.Execute (System.Object parameter) [0x00000] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Core\Command.cs:107 at Xamarin.Forms.Button.Xamarin.Forms.IButtonController.SendClicked () [0x0000a] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Core\Button.cs:121 at Xamarin.Forms.Platform.Android.AppCompat.ButtonRenderer+ButtonClickListener.OnClick (Android.Views.View v) [0x0000b] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\AppCompat\ButtonRenderer.cs:298 at Android.Views.View+IOnClickListenerInvoker.n_OnClick_Landroid_view_View_ (System.IntPtr jnienv, System.IntPtr native__this, System.IntPtr native_v) [0x0000f] in <71828dd8fb5f4508815e23d6996c45c2>:0 at (wrapper dynamic-method) System.Object:4c9f6786-8ab0-4bd8-bdb1-4cc7a3d7ddc7 (intptr,intptr,intptr) -> (Inner Exception #0) System.InvalidCastException: Specified cast is not valid. at Catel.Services.UIVisualizerService+<ShowAsync>d__9.MoveNext () [0x00096] in C:\CI_WS\Ws\97969\Source\Catel\src\Catel.MVVM\Catel.MVVM.Xamarin.Forms\Services\UIVisualizerService.cs:151 <---

我做什么：

• 将android 项目中的默认Catel.MVVM.dll 引用从MonoAndroid 更改为portable-net45+wp8+win8+wpa81+MonoAndroid10+MonoTouch10+Xamarin.iOS10+UAP10。如果不这样做，编译将失败。

• MainPage.xaml

  <catel:ContentPage ... xmlns:catel="clr-namespace:Catel.Windows.Controls;assembly=Catel.MVVM">

• MainPageViewModel.cs

  public class MainPageViewModel : ViewModelBase { }

• App.cs

  public class App : Catel.Xamarin.Forms.Application<Views.MainPage> { }

• MainActivity.cs (Android)

  public class MainActivity : Xamarin.Forms.Platform.Android.FormsAppCompatActivity
  {
      protected override void OnCreate( Bundle bundle )
      {
          TabLayoutResource = Resource.Layout.Tabbar;
          ToolbarResource = Resource.Layout.Toolbar;
  
          base.OnCreate( bundle );
  
          Xamarin.Forms.Forms.Init( this, bundle );
  
          var app = new App();
          LoadApplication( app );
      }
  }
  

Windows 7、64x。 Xamarin.Forms：2.3.4.267

非常感谢任何帮助。

Answer 1

团队正在努力改进对 Xamarin.Forms 的支持。目前没有例子。期望在接下来的几个月内最终确定对 Xamarin.Forms 的 v5 支持。