開發環境:vs2017目標框架：<TargetFramework>netcoreapp1.1</TargetFramework><PackageTargetFallback>$(PackageTargetFallback);portable-net45+win8+wp8+wpa81;</PackageTargetFallback>命令： dotnet ef migrations add VotePeriodV2 錯誤：Startup project '*.*.*.csproj' targets framework '.NETCoreApp' version '1.1'. This version of the Entity Framework Core .NET Command-line Tools only supports version 2.0 or higher. For information on using older versions of the tools, see https://go.microsoft.com/fwlink/?linkid=871254