小编Rah*_*til的帖子

项目版本：.netcore2.2

我正在 .netcore2.2 中使用 N 层架构

当我定义以下配置时给出错误：

DbContextOptionsBuilder”不包含“usesqlserver”的定义，并且没有扩展方法“usesqlserver”

    public class CustomerDataAccess : DbContext, ICustomerDataAccess
    {

        protected override void OnConfiguring(DbContextOptionsBuilder dbContextOptionsBuilder)
        {
            if (!dbContextOptionsBuilder.IsConfigured && _configuration.GetConnectionString("DMEBaseConnection") != null)
            {
                dbContextOptionsBuilder.UseSqlServer(_configuration.GetConnectionString("connectionstringname")); **//here give an error**
            }
        }

启动.cs

    public class Startup
    {
        // This method gets called by the runtime. Use this method to add services to the container.
        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
        public void ConfigureServices(IServiceCollection services)
        {
        }

        // This method gets called …