使用实体框架中的输出参数执行SQL存储过程

Using EF, I'm trying to execute a stored procedure that returns a single string value, i.e. the status of an SQL Agent Job.

使用EF，我正在尝试执行一个返回单个字符串值的存储过程，即SQL代理作业的状态。

The stored procedure is declared as

存储过程声明为

CREATE PROCEDURE [dbo].[up_GetJobStatus](@JobStatus NVARCHAR(30) OUTPUT)
AS

-- some code omitted for brevity

SELECT @JobStatus = (
SELECT  
    CASE job_state 
    WHEN 1 THEN 'Executing'
    WHEN 2 THEN 'Waiting for thread'
    WHEN 3 THEN 'Between retries'
    WHEN 4 THEN 'Idle'
    WHEN 5 THEN 'Suspended'
    WHEN 6 THEN '<unknown>'
    WHEN 7 THEN 'Performing completion actions'
END
FROM @xp_results results 
INNER JOIN msdb.dbo.sysjobs sj
ON results.job_id = sj.job_id
WHERE sj.job_id = @job_id)

RETURN

I have verified the stored procedure is working correct as I can execute it in query window and it returns

我已验证存储过程是否正常，因为我可以在查询窗口中执行它并返回

    @JobStatus
  ------------
  1|Idle

However when executing with EF, the param value is NULL

但是，在使用EF执行时，param值为NULL

var param = new SqlParameter
{
    ParameterName = "@JobStatus",
    DbType = DbType.String,
    Size = 30,
    Direction = System.Data.ParameterDirection.Output
};

var result = this.etlContext.Database.SqlQuery<string>("EXEC dbo.up_GetJobStatus @JobStatus OUTPUT", param);

I've also tried the ExecuteSqlCommand method but that didn't work either.

我也尝试过ExecuteSqlCommand方法但是也没用。

Any ideas?

有任何想法吗？

3 个解决方案

#1

1. Create stored procedure in database
2. 在数据库中创建存储过程

.

。

 CREATE PROCEDURE [dbo].myStoredProcName
    @inputParam1 varchar(150),
    @inputParam2 varchar(150),
    @myOutputParamBool bit output,
    @myOutputParamString varchar(100) output,
    @myOutputParamInt int output
AS
BEGIN
    -- sql here
END

2. Update entity model from database to include stored procedure as shown here

   从数据库更新实体模型以包括存储过程，如下所示

3. Call stored proc from C# code

   从C＃代码调用存储过程

.

。

System.Data.Entity.Core.Objects.ObjectParameter myOutputParamBool=new System.Data.Entity.Core.Objects.ObjectParameter("myOutputParamBool",typeof(bool));

System.Data.Entity.Core.Objects.ObjectParameter myOutputParamString=new System.Data.Entity.Core.Objects.ObjectParameter("myOutputParamString",typeof(string));

System.Data.Entity.Core.Objects.ObjectParameter myOutputParamInt=new System.Data.Entity.Core.Objects.ObjectParameter("myOutputParamInt",typeof(Int32));

using (var context = new SandCryptEntities())
{
   context.myStoredProcName(inputParam1, inputParam2, myOutputParamBool, myOutputParamString, myOutputParamInt);   
}
            bool myBool = Convert.ToBoolean(myOutputParamBool.Value);
            string myString = Convert.ToString(myOutputParamString.Value);
            int myInt = Convert.ToInt32(myOutputParamInt.Value);

#2

Here's an actual answer. Apparently there are serious issues with output parameters in entity framework when you're using DbContext/code first. This article has a good discussion and workaround: http://weblogs.asp.net/dwahlin/using-entity-framework-code-first-with-stored-procedures-that-have-output-parameters. Apparently it's supposed to be "fixed" with an update, but I haven't really seen that happen.

这是一个实际的答案。显然，当您首先使用DbContext /代码时，实体框架中的输出参数存在严重问题。本文有一个很好的讨论和解决方法：http：//weblogs.asp.net/dwahlin/using-entity-framework-code-first-with-stored-procedures-that-have-output-parameters。显然它应该通过更新来“修复”，但我还没有真正看到过这种情况。

#3

Please review this link to execute your stored procedure and retrieve the output parameter. You will first need to import the stored procedure into your dbmx.

请查看此链接以执行存储过程并检索输出参数。您首先需要将存储过程导入dbmx。