Visual studio 生成模板项目时出错-移动应用程序（Xamarin表单）-Visual Studio 2017

Xamarin表单应用程序的项目模板无法开箱即用？只是选择使用母版详细信息页和.Net标准库创建一个新的移动应用程序（Xamarin表单）。这就是结果

顺便说一句，在Windows 10 v 1703 OS Build 15063.0上使用全新安装的Visual Studio 2017社区（15.8.2版）。这应该是工作，我检查了所有正确的选项在安装程序

Severity    Code    Description Project File    Line    Suppression State
Error   CS0246  The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    2   Active
Error   CS0246  The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    2   Active
Error   CS0246  The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    3   Active
Error   CS0246  The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    3   Active
Error   CS0246  The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    4   Active
Error   CS0246  The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    4   Active
Error   CS0246  The type or namespace name 'Xamarin' could not be found (are you missing a using directive or an assembly reference?)   MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    5   Active
Error   CS0246  The type or namespace name 'Xamarin' could not be found (are you missing a using directive or an assembly reference?)   MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    5   Active
Error   CS0246  The type or namespace name 'Xamarin' could not be found (are you missing a using directive or an assembly reference?)   MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    6   Active
Error   CS0246  The type or namespace name 'Xamarin' could not be found (are you missing a using directive or an assembly reference?)   MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    6   Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    10  Active
Error   CS0246  The type or namespace name 'XamlCompilationAttribute' could not be found (are you missing a using directive or an assembly reference?)  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    10  Active
Error   CS0246  The type or namespace name 'XamlCompilation' could not be found (are you missing a using directive or an assembly reference?)   MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    10  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    10  Active
Error   CS0103  The name 'XamlCompilationOptions' does not exist in the current context MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    10  Active
Error   CS0246  The type or namespace name 'MasterDetailPage' could not be found (are you missing a using directive or an assembly reference?)  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    11  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    13  Active
Error   CS0246  The type or namespace name 'Dictionary<,>' could not be found (are you missing a using directive or an assembly reference?) MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    13  Active
Error   CS0518  Predefined type 'System.Int32' is not defined or imported   MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    13  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    13  Active
Error   CS0246  The type or namespace name 'NavigationPage' could not be found (are you missing a using directive or an assembly reference?)    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    13  Active
Error   CS0518  Predefined type 'System.Void' is not defined or imported    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    14  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    23  Active
Error   CS0246  The type or namespace name 'Task' could not be found (are you missing a using directive or an assembly reference?)  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    23  Active
Error   CS1983  The return type of an async method must be void, Task or Task<T>    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    23  Active
Error   CS0518  Predefined type 'System.Int32' is not defined or imported   MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    23  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    13  Active
Error   CS0246  The type or namespace name 'Dictionary<,>' could not be found (are you missing a using directive or an assembly reference?) MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    13  Active
Error   CS0518  Predefined type 'System.Int32' is not defined or imported   MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    13  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    13  Active
Error   CS0246  The type or namespace name 'NavigationPage' could not be found (are you missing a using directive or an assembly reference?)    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    13  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    16  Active
Error   CS0103  The name 'InitializeComponent' does not exist in the current context    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    16  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    18  Active
Error   CS0103  The name 'MasterBehavior' does not exist in the current context MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    18  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    18  Active
Error   CS0103  The name 'MasterBehavior' does not exist in the current context MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    18  Active
Error   CS0518  Predefined type 'System.Enum' is not defined or imported    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    20  Active
Error   CS0518  Predefined type 'System.Int32' is not defined or imported   MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    20  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    20  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    20  Active
Error   CS0246  The type or namespace name 'NavigationPage' could not be found (are you missing a using directive or an assembly reference?)    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    20  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    20  Active
Error   CS0103  The name 'Detail' does not exist in the current context MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    20  Active
Error   CS0161  'MainPage.NavigateFromMenu(int)': not all code paths return a value MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    23  Active
Error   CS0518  Predefined type 'System.Boolean' is not defined or imported MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    25  Active
Error   CS0518  Predefined type 'System.Enum' is not defined or imported    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    29  Active
Error   CS0518  Predefined type 'System.Int32' is not defined or imported   MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    29  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    29  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    30  Active
Error   CS0246  The type or namespace name 'NavigationPage' could not be found (are you missing a using directive or an assembly reference?)    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    30  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    30  Active
Error   CS0518  Predefined type 'System.Enum' is not defined or imported    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    32  Active
Error   CS0518  Predefined type 'System.Int32' is not defined or imported   MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    32  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    32  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    33  Active
Error   CS0246  The type or namespace name 'NavigationPage' could not be found (are you missing a using directive or an assembly reference?)    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    33  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    33  Active
Error   CS0518  Predefined type 'System.Boolean' is not defined or imported MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    40  Active
Error   CS0518  Predefined type 'System.Boolean' is not defined or imported MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    40  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    40  Active
Error   CS0103  The name 'Detail' does not exist in the current context MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    40  Active
Error   CS0518  Predefined type 'System.Boolean' is not defined or imported MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    40  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    42  Active
Error   CS0103  The name 'Detail' does not exist in the current context MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    42  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    44  Active
Error   CS0103  The name 'Device' does not exist in the current context MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    44  Active
Error   CS0518  Predefined type 'System.Boolean' is not defined or imported MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    44  Active
Error   CS0518  Predefined type 'System.Boolean' is not defined or imported MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    44  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    44  Active
Error   CS0103  The name 'Device' does not exist in the current context MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    44  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    45  Active
Error   CS0103  The name 'Task' does not exist in the current context   MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    45  Active
Error   CS0518  Predefined type 'System.Int32' is not defined or imported   MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    45  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    47  Active
Error   CS0103  The name 'IsPresented' does not exist in the current context    MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    47  Active
Error   CS0518  Predefined type 'System.Boolean' is not defined or imported MyApp_X D:\SOURCECODE\MyApp_X\MyApp_X\MyApp_X\Views\MainPage.xaml.cs    47  Active
Error       The "Xamarin.Forms.Build.Tasks.GetTasksAbi" task could not be loaded from the assembly C:\Users\erot\.nuget\packages\xamarin.forms\3.1.0.697729\build\netstandard2.0\Xamarin.Forms.Build.Tasks.dll. Could not load file or assembly 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies. The system cannot find the file specified. Confirm that the <UsingTask> declaration is correct, that the assembly and all its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask.   MyApp_X.UWP         
Warning IDE0006 Error encountered while loading the project. Some project features, such as full solution analysis for the failed project and projects that depend on it, have been disabled.   MyApp_X.Android     1   Active
Warning     The "Xamarin.Forms.Build.Tasks.GetTasksAbi" task could not be loaded from the assembly C:\Users\erot\.nuget\packages\xamarin.forms\3.1.0.697729\build\netstandard2.0\Xamarin.Forms.Build.Tasks.dll. Could not load file or assembly 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies. The system cannot find the file specified. Confirm that the <UsingTask> declaration is correct, that the assembly and all its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask.   MyApp_X.Android         
Warning IDE0006 Error encountered while loading the project. Some project features, such as full solution analysis for the failed project and projects that depend on it, have been disabled.   MyApp_X.UWP     1   Active
Error   MSB4062 The "Xamarin.Forms.Build.Tasks.XamlGTask" task could not be loaded from the assembly C:\Users\erot\.nuget\packages\xamarin.forms\3.1.0.697729\build\netstandard2.0\Xamarin.Forms.Build.Tasks.dll. Could not load file or assembly 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies. The system cannot find the file specified. Confirm that the <UsingTask> declaration is correct, that the assembly and all its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask. MyApp_X C:\Users\erot\.nuget\packages\xamarin.forms\3.1.0.697729\build\netstandard2.0\Xamarin.Forms.targets 84  
Error   MSB4062 The "Xamarin.Forms.Build.Tasks.GetTasksAbi" task could not be loaded from the assembly C:\Users\erot\.nuget\packages\xamarin.forms\3.1.0.697729\build\netstandard2.0\Xamarin.Forms.Build.Tasks.dll. Could not load file or assembly 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies. The system cannot find the file specified. Confirm that the <UsingTask> declaration is correct, that the assembly and all its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask.   MyApp_X C:\Users\erot\.nuget\packages\xamarin.forms\3.1.0.697729\build\netstandard2.0\Xamarin.Forms.targets 36  

严重性代码描述项目文件行抑制状态
错误CS0246找不到类型或命名空间名称“System”（是否缺少using指令或程序集引用？）MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 2处于活动状态
错误CS0246找不到类型或命名空间名称“System”（是否缺少using指令或程序集引用？）MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 2处于活动状态
错误CS0246找不到类型或命名空间名称“System”（是否缺少using指令或程序集引用？）MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 3处于活动状态
错误CS0246找不到类型或命名空间名称“System”（是否缺少using指令或程序集引用？）MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 3处于活动状态
错误CS0246找不到类型或命名空间名称“System”（是否缺少using指令或程序集引用？）MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 4处于活动状态
错误CS0246找不到类型或命名空间名称“System”（是否缺少using指令或程序集引用？）MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 4处于活动状态
错误CS0246找不到类型或命名空间名称“Xamarin”（是否缺少using指令或程序集引用？）
错误CS0246找不到类型或命名空间名称“Xamarin”（是否缺少using指令或程序集引用？）
错误CS0246找不到类型或命名空间名称“Xamarin”（是否缺少using指令或程序集引用？）
错误CS0246找不到类型或命名空间名称“Xamarin”（是否缺少using指令或程序集引用？）
错误CS0518未定义或导入预定义类型“System.Object”MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 10活动
错误CS0246找不到类型或命名空间名称“XamlcomilationAttribute”（是否缺少using指令或程序集引用？）MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 10处于活动状态
错误CS0246找不到类型或命名空间名称“Xamlcomilation”（是否缺少using指令或程序集引用？）MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 10处于活动状态
错误CS0518未定义或导入预定义类型“System.Object”MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 10活动
错误CS0103当前上下文MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 10中不存在名称“XAMLCompliationOptions”
错误CS0246找不到类型或命名空间名称“MasterDetailPage”（是否缺少using指令或程序集引用？）
错误CS0518未定义或导入预定义类型“System.Object”MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 13活动
错误CS0246找不到类型或命名空间名称“Dictionary”（是否缺少using指令或程序集引用？）MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 13处于活动状态
错误CS0518未定义或导入预定义类型“System.Int32”MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 13活动
错误CS0518未定义或导入预定义类型“System.Object”MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 13活动
错误CS0246找不到类型或命名空间名称“NavigationPage”（是否缺少using指令或程序集引用？）
错误CS0518未定义或导入预定义类型“System.Void”MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 14活动
错误CS0518未定义或导入预定义类型“System.Object”MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 23活动
错误CS0246找不到类型或命名空间名称“Task”（是否缺少using指令或程序集引用？）MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 23处于活动状态
错误CS1983异步方法的返回类型必须为void，Task或Task MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 23处于活动状态
错误CS0518未定义或导入预定义类型“System.Int32”MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 23活动
错误CS0518未定义或导入预定义类型“System.Object”MyApp\u X D:\SOURCECODE\MyApp\u X\MyApp\u X\Views\MainPage.xaml.cs 13活动
错误CS0246找不到类型或命名空间名称“Dictionary”（您是否缺少using指令或