EF调用存储过程,获取output参数返回的值

我们新建了一个存储过程，它可能是一个计算的存储过程，或者处理一系列sql语句后，我们需要返回一个结果给调用的语言代码。

如下存储过程，输出一个num值参数

USE [HY_ReplyComment]  
GO  
/****** 对象:  StoredProcedure [dbo].[AddVote]    脚本日期: 06/10/2014 22:27:11 ******/  
SET ANSI_NULLS ON  
GO  
SET QUOTED_IDENTIFIER ON  
GO  
  
-- =============================================  
-- Author:        <Author,,Name>  
-- Create date: <Create Date,,>  
-- Description:    <Description,,>  
-- =============================================  
CREATE PROCEDURE [dbo].[AddVote]   
    @blockId int,  
    @num int output  
AS  
BEGIN  
    -- SET NOCOUNT ON added to prevent extra result sets from  
    -- interfering with SELECT statements.  
    SET NOCOUNT ON;  
  
    SELECT @num = Count(1) FROM [Vote] WHERE TitleId =1 AND BlockId = 2
  
END 

public virtual int AddVote(Nullable<System.int> blockId, ObjectParameter num)
        {
            var mainIDParameter = blockId.HasValue ?
                new ObjectParameter("blockId", blockId) :
                new ObjectParameter("blockId", typeof(System.int));
    
            return ((IObjectContextAdapter)this).ObjectContext.ExecuteFunction("AddVote", blockIdParameter, num);
        }

using (var db = new EBSCreditEntities())
                    {
                        var num = new System.Data.Entity.Core.Objects.ObjectParameter("num", typeof(int));

                        int rst = db.AddVote(m.blockId, num);
                        int num = int.Parse(num == null ? "0" : num.Value.ToString());
                    }