System.InvalidCastException: 'The SqlParameterCollection only accepts non-null SqlParameter type objects, not SqlParameter objects.'

问题

I migrated my project from ASP.NET Core 2.2 to ASP.NET Core 3.0. Now I get this exception. In ASP.NET Core it was using FromSql - now it is using FromSqlRaw. I am calling my procedure using Entity Framework Core.

SqlParameter Username = new SqlParameter
            {
                ParameterName = "USERNAME",
                SqlDbType = SqlDbType.NVarChar,
                Value = user.Username,
                Direction = ParameterDirection.Input,
                Size = 50
            };

SqlParameter Password = new SqlParameter
            {
                ParameterName = "PASSWORD",
                SqlDbType = SqlDbType.NVarChar,
                Value = user.Password,
                Direction = ParameterDirection.Input,
                Size = 50
            };

SqlParameter msgOut = new SqlParameter
            {
                ParameterName = "MSG",
                SqlDbType = SqlDbType.NVarChar,
                Direction = ParameterDirection.Output,
                Size = 1000
            };

SqlParameter statusOut = new SqlParameter
            {
                ParameterName = "STATUS",
                SqlDbType = SqlDbType.Int,
                Direction = ParameterDirection.Output
            };

var sql = @"EXEC PRC_USERS_LOGIN
                        @USERNAME, 
                        @PASSWORD, 
                        @MSG OUT, 
                        @STATUS OUT";

Users resultUser = new Users();
resultUser = ctx.Users.FromSqlRaw(sql, Username, Password, msgOut, statusOut)
                      .FirstOrDefault();

回答1:

Fixed by changing using System.Data.SqlClient to using Microsoft.Data.SqlClient

https://github.com/aspnet/EntityFrameworkCore/issues/16812#issuecomment-516013245

回答2:

This code worked after replacing

System.Data.SqlClient.SqlParameter

to

Microsoft.Data.SqlClient.SqlParameter

and

FirstOrDefault();

to

ToList();

来源：https://stackoverflow.com/questions/58153228/system-invalidcastexception-the-sqlparametercollection-only-accepts-non-null-s