System.ArgumentException: 'The specified invariant name 'System.Data.SqlClient' wasn't found in the list of registered .NET Data Providers.'

在.net core中，需要自己注册数据库访问程序：

 DbProviderFactories.RegisterFactory("System.Data.SqlClient", SqlClientFactory.Instance);

 

https://stackoverflow.com/questions/52007836/dbproviderfactories-getfactoryclasses-returns-no-results-after-installing-net-s