从C#中的存储过程返回值

using System;
using System.Data.SqlClient;

class Program
{
    static void Main()
    {
        string connectionString = "Data Source=localhost;Initial Catalog=Northwind;Integrated Security=True";
        string storedProcedureName = "dbo.GetOrderTotal";

        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            SqlCommand command = new SqlCommand(storedProcedureName, connection);
            command.CommandType = System.Data.CommandType.StoredProcedure;

            SqlParameter parameter = new SqlParameter("@OrderId", SqlDbType.Int);
            parameter.Value = 10248;
            command.Parameters.Add(parameter);

            SqlParameter returnValue = command.Parameters.Add("@ReturnValue", SqlDbType.Int);
            returnValue.Direction = System.Data.ParameterDirection.ReturnValue;

            connection.Open();
            command.ExecuteNonQuery();

            int result = (int)returnValue.Value;
            Console.WriteLine("The total for order 10248 is: " + result);
        }
    }
}