我有一个Xamarin形式的项目，我正在其中使用Sqlite数据库，现在我想将此Sqlite转换为Microsoft.EntityFrameworkCore.Sqlite，但我发现了此异常。
Severity Code Description Project File Line Suppression
State
Error Could not install package 'Microsoft.EntityFrameworkCore.Sqlite 3.0.0-preview6.19304.10'. You are trying to install this package into a project that targets '.NETPortable,Version=v4.5,Profile=Profile259', but the package does not contain any assembly references or content files that are compatible with that framework. For more information, contact the package author.
我的项目中有3个项目面向.NET FrameWork 4.5，但是Microsoft.EntityFrameworkCore.Sqlite要求 .NET Standered 2.0 。