相关疑难解决方法(0)

我有以下查询:

set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON
go

ALTER PROCEDURE [dbo].[Validate]
@a varchar(50),
@b varchar(50) output

AS

SET @Password = 
(SELECT Password
FROM dbo.tblUser
WHERE Login = @a)

RETURN @b
GO

这个编译完全没问题.

在C#中,我想执行此查询并获取返回值.

我的代码如下:

  SqlConnection SqlConn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["MyLocalSQLServer"].ConnectionString.ToString());
        System.Data.SqlClient.SqlCommand sqlcomm = new System.Data.SqlClient.SqlCommand("Validate", SqlConn);

        string returnValue = string.Empty;

        try
        {
            SqlConn.Open();
            sqlcomm.CommandType = CommandType.StoredProcedure;

            SqlParameter param = new SqlParameter("@a", SqlDbType.VarChar);
            param.Direction = ParameterDirection.Input;
            param.Value = Username;
            sqlcomm.Parameters.Add(param);



            SqlParameter retval = sqlcomm.Parameters.Add("@b", SqlDbType.VarChar);
            retval.Direction = ParameterDirection.ReturnValue;


            string retunvalue = (string)sqlcomm.Parameters["@b"].Value; …