.Net 调用存储过程取到return的返回值

SET ANSI_NULLS ON 
GO 
SET QUOTED_IDENTIFIER ON 
GO 
-- ============================================= 
-- Author: <Author,,Name> 
-- Create date: <Create Date,,> 
-- Description: <Description,,> 
-- ============================================= 
alter PROCEDURE GetOrderLine 
@orderId varchar(50) 
AS 
BEGIN 
-- SET NOCOUNT ON added to prevent extra result sets from 
-- interfering with SELECT statements. 
SET NOCOUNT ON; 

select  from orderLine where OrderId = @orderId; 

return 123; 
END 
GO

DataTable dt = new DataTable(); 
string connStr = System.Configuration.ConfigurationManager.ConnectionStrings["BLL.Properties.Settings.ShoppingDBConnectionString"].ToString(); 
using(SqlConnection conn= new SqlConnection(connStr)){ 
string callName = "GetOrderLine"; 
using (SqlCommand mand = new SqlCommand(callName, conn)) 
{ 
mand.CommandType = CommandType.StoredProcedure; 
SqlParameter[] sps = { new SqlParameter("@orderId",SqlDbType.VarChar,50) , 
new SqlParameter("@return",SqlDbType.Int) //注册返回值类型 
}; 

sps[0].Value = "43c7cf15-6b2f-4d18-92b2-dbe827f30dfc"; 
sps[1].Direction = ParameterDirection.ReturnValue; //返回参数类型 

mand.Parameters.AddRange(sps); 
using(SqlDataAdapter sda =new SqlDataAdapter()){ 
sda.SelectCommand = mand; 
sda.Fill(dt); 
//Console.WriteLine(sda.GetFillParameters()[1].Value); 
Console.WriteLine(sps[1].Value); //取到返回的值 
} 

} 
} 

if(dt.Rows.Count>0){ 
for (int i = 0; i < dt.Rows.Count;i++ ) 
{ 
Console.WriteLine(dt.Rows[i]["ProductId"]+":"+dt.Rows[i]["ProductPrice"]+":"+dt.Rows[i]["ProductCount"]); 
} 
} 
Console.ReadLine();