xamarin android 报错 Could not load assembly 'Xamarin.Android.Support.v7.AppCompat

严重性    代码    说明    项目    文件    行    禁止显示状态
错误        Exception while loading assemblies: System.IO.FileNotFoundException: Could not load assembly 'Xamarin.Android.Support.v7.AppCompat, Version=1.0.0.0, Culture=neutral, PublicKeyToken='. Perhaps it doesn't exist in the Mono for Android profile?
文件名:“Xamarin.Android.Support.v7.AppCompat.dll”
   在 Java.Interop.Tools.Cecil.DirectoryAssemblyResolver.Resolve(AssemblyNameReference reference, ReaderParameters parameters)
   在 Xamarin.Android.Tasks.ResolveAssemblies.AddAssemblyReferences(DirectoryAssemblyResolver resolver, ICollection`1 assemblies, AssemblyDefinition assembly, Boolean topLevel)
   在 Xamarin.Android.Tasks.ResolveAssemblies.Execute(DirectoryAssemblyResolver resolver)    ToolbarFun            

经对比发现应该是vs的bug，当创建了 Forms ContentView后就一直报这个错误，对比发现只要删除 .csproj 文件中的下面这段，即可以解决此问题：

<Reference Include="Xamarin.Forms.Core, Version=2.0.0.0, Culture=neutral, processorArchitecture=MSIL">
      <HintPath>..\packages\Xamarin.Forms.2.3.3.193\lib\MonoAndroid10\Xamarin.Forms.Core.dll</HintPath>
    </Reference>
    <Reference Include="Xamarin.Forms.Platform, Version=1.0.0.0, Culture=neutral, processorArchitecture=MSIL">
      <HintPath>..\packages\Xamarin.Forms.2.3.3.193\lib\MonoAndroid10\Xamarin.Forms.Platform.dll</HintPath>
    </Reference>
    <Reference Include="Xamarin.Forms.Platform.Android, Version=2.0.0.0, Culture=neutral, processorArchitecture=MSIL">
      <HintPath>..\packages\Xamarin.Forms.2.3.3.193\lib\MonoAndroid10\Xamarin.Forms.Platform.Android.dll</HintPath>
    </Reference>
    <Reference Include="Xamarin.Forms.Xaml, Version=2.0.0.0, Culture=neutral, processorArchitecture=MSIL">
      <HintPath>..\packages\Xamarin.Forms.2.3.3.193\lib\MonoAndroid10\Xamarin.Forms.Xaml.dll</HintPath>
    </Reference>