原文地址：http://blogs.microsoft.co.il/gilf/2010/05/09/how-to-retrieve-stored-procedure-output-parameters-in-entity-framework/ 

 

How to Retrieve Stored Procedure Output Parameters in Entity Framework

 

One question that 

raises from time to 

time in EF forums 

is how you can 

retrieve stored 

procedure output 

parameters in EF 

Function Import. 

This post will show you how to do that.

 

The Stored Procedure

 

In the example I’m going to use the following stored procedure:

 

CREATE PROCEDURE dbo.SchoolBudgetForDateRange

@StartDate DATETIME,

@EndDate DATETIME,

@Sum money output

AS

SET NOCOUNT ON;

SELECT @Sum = SUM(Department.Budget)

FROM Department

WHERE StartDate BETWEEN @StartDate AND @EndDate

 

The stored procedure returns the school budget for a given date. 

By of course the stored procedure could return that calculation 

without using an output parameter.

 

Retrieving Stored Procedure Output Parameter

 

After creating a Function Import (which is explained ) we can 

use the SchoolBudgetforDateRange method with the context we have. 

In order to get an output parameter you need to supply an ObjectParameter 

to the stored procedure call which holds the parameter name and type. 

After the execution of the stored procedure you can retrieve the 

parameter using the Value property of the ObjectParameter. 

The following code shows how to that exactly what I wrote:

 

static void Main(string[] args)

{

using (SchoolEntities context = new SchoolEntities())

{

var outputParameter = new ObjectParameter(“sum”, typeof(decimal));

context.SchoolBudgetForDateRange(new DateTime(2007, 1, 1),

new DateTime(2008, 1, 1),

outputParameter);

Console.WriteLine(outputParameter.Value);

}

}

 

Summary

 

 

 

Once you need to retrieve output parameters from EF Function Imports, 

you need to supply an ObjectParameter to hold the output. In the post 

I showed how to do that.

 

----------------------------------------

自我测试

ALTER PROC [dbo].[usp_AddTeacherInfo]

@Name NVARCHAR(50),

@Phone NVARCHAR(50),

@Address NVARCHAR(50),

@Age INT,

@Sum UNIQUEIDENTIFIER OUTPUT

AS

BEGIN

SET NOCOUNT ON

DECLARE @TmpID UNIQUEIDENTIFIER

SET @TmpID = NEWID()

INSERT INTO dbo.Teacher

(ID, Name, Phone, Address, Age )

VALUES ( @TmpID,@Name,@Phone,@Address,@Age)

SET @Sum = @TmpID

SET NOCOUNT OFF

END

 

public void AddTeacherInfo()

{

using (DemoDBEntities entity = new DemoDBEntities())

{

var outputParameter = new ObjectParameter("sum", typeof(Guid));

var dd = entity.usp_AddTeacherInfo("dapeng", "021-99999999", "address222", 86, outputParameter);

}

}