【发布时间】：2019-12-17 03:48:38
【问题描述】：
我正在使用 .NET 和 Xamarin 在 Visual Studio 中开发一个简单的 Android 应用程序。一切都很顺利，除了我似乎缺少某些 UI 元素。具体来说，我错过了 Spinner 类。在为 Android Xamarin 开发设置 Visual Studio 2019 时，我应该做些什么简单的事情来使这些可用？
当我尝试在 XAML 文件中包含 Spinner 时出现以下错误：
The type 'Spinner' was not found. Verify that you are not missing an assembly reference and that all referenced assemblies have been built.
现在可能是 Android 小部件在 Xamarin 中不可用 - 如果是这种情况，请让我直截了当。不过，我无法通过我的研究确认是否是这种情况。
这是我的 Visual Studio 构建、Xamarin 等的所有版本信息。我正在为 Android 9.0 构建。
Microsoft Visual Studio Community 2019
Version 16.4.1
VisualStudio.16.Release/16.4.1+29609.76
Microsoft .NET Framework
Version 4.7.03056
Installed Version: Community
Azure App Service Tools v3.0.0 16.4.457.38025
Azure App Service Tools v3.0.0
C# Tools 3.4.1-beta4-19607-02+52d275c4f82f329a9732b078c7f7fa0e45cd3e84
C# components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used.
Common Azure Tools 1.10
Provides common services for use by Azure Mobile Services and Microsoft Azure Tools.
Extensibility Message Bus 1.2.0 (d16-2@8b56e20)
Provides common messaging-based MEF services for loosely coupled Visual Studio extension components communication and integration.
IntelliCode Extension 1.0
IntelliCode Visual Studio Extension Detailed Info
Microsoft JVM Debugger 1.0
Provides support for connecting the Visual Studio debugger to JDWP compatible Java Virtual Machines
Microsoft MI-Based Debugger 1.0
Provides support for connecting Visual Studio to MI compatible debuggers
Mono Debugging for Visual Studio 16.5.23 (1b51e8c)
Support for debugging Mono processes with Visual Studio.
NuGet Package Manager 5.4.0
NuGet Package Manager in Visual Studio. For more information about NuGet, visit https://docs.nuget.org/
ProjectServicesPackage Extension 1.0
ProjectServicesPackage Visual Studio Extension Detailed Info
Visual Basic Tools 3.4.1-beta4-19607-02+52d275c4f82f329a9732b078c7f7fa0e45cd3e84
Visual Basic components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used.
Visual F# Tools 10.4 for F# 4.6 16.4.0-beta.19556.5+e7597deb7042710a7142bdccabd6f92b0840d354
Microsoft Visual F# Tools 10.4 for F# 4.6
Visual Studio Code Debug Adapter Host Package 1.0
Interop layer for hosting Visual Studio Code debug adapters in Visual Studio
VisualStudio.DeviceLog 1.0
Information about my package
VisualStudio.Foo 1.0
Information about my package
VisualStudio.Mac 1.0
Mac Extension for Visual Studio
Xamarin 16.4.000.306 (d16-4@564b8d0)
Visual Studio extension to enable development for Xamarin.iOS and Xamarin.Android.
Xamarin Designer 16.4.0.464 (remotes/origin/d16-4@4abf337c3)
Visual Studio extension to enable Xamarin Designer tools in Visual Studio.
Xamarin Templates 16.4.25 (579ee62)
Templates for building iOS, Android, and Windows apps with Xamarin and Xamarin.Forms.
Xamarin.Android SDK 10.1.1.0 (d16-4/f2c9364)
Xamarin.Android Reference Assemblies and MSBuild support.
Mono: bef1e63
Java.Interop: xamarin/java.interop/d16-4@c4e569f
ProGuard: xamarin/proguard/master@905836d
SQLite: xamarin/sqlite/3.28.0@46204c4
Xamarin.Android Tools: xamarin/xamarin-android-tools/master@9f4ed4b
Xamarin.iOS and Xamarin.Mac SDK 13.8.3.0 (0d8fe21)
Xamarin.iOS and Xamarin.Mac Reference Assemblies and MSBuild support.
【问题讨论】：
-
您使用哪个版本的 Xamarin Forms？什么 Android 操作系统级别的目标？请详细说明。
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复制/粘贴 Visual Studio 版本信息，以防万一。
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@Trekkie，你想在 Xamarin.forms 中使用 Spinner 吗？我认为是Xamarin.Forms中的控件，我想你可以用这个来替换spinner：github.com/amccorma/xamarin-amccorma/tree/master/Forms.DropDown
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这似乎可行，但我的问题是为什么我一开始就想念 Spinner
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@Trekkie，很抱歉我的第一个评论，我认为微调器不是 Xamarin.forms 中的控件，您想在 PCL 中使用它吗？它可以在Android中使用。