c# - 如何在 C# 中获取 SQL Server 存储过程的返回值？

Question

我是 C# 和 SQL Server 的初学者，我编写了这个查询以在 SQL Server 中创建存储过程:

create procedure newBehzad 
    @id bigint
as
    DECLARE @ResultValue int

    select *
    from TABLEA
    where id > @id

    SET  @ResultValue = -5
go

一切正常，我编写了这段 C# 代码来调用该存储过程并返回一个值:

using (var conn = new SqlConnection(connectionString))
using (var command = new SqlCommand("newBehzad", conn)
{
    CommandType = CommandType.StoredProcedure
})
{
    conn.Open();

    command.Parameters.Add("@id", SqlDbType.BigInt).Value = 2;
    command.Parameters.Add("@ResultValue", SqlDbType.Int);

    SqlParameter retval = command.Parameters.Add("@ResultValue", SqlDbType.Int);
    retval.Direction = ParameterDirection.ReturnValue;

    retunvalue = (string)command.Parameters["@ResultValue"].Value;

    //SqlParameter retval = sqlcomm.Parameters.Add("@b", SqlDbType.VarChar);
    command.ExecuteNonQuery();
    conn.Close();
}

MessageBox.Show(returnValue);

但是当我运行 C# windows 应用程序时，我得到这个错误:

Procedure or function newBehzad has too many arguments specified.

我该如何解决？谢谢。

Answer 1

将您的程序更改为:

create procedure newBehzad @id bigint, @ResultValue int OUT
as
SET  @ResultValue = 0
BEGIN
    select *from TABLEA
    where id>@id
    SET  @ResultValue = -5
END
go

请尝试这样想:

object returnValue = null;
            using (var conn = new System.Data.SqlClient.SqlConnection(AbaseDB.DBFactory.GetInstance().GetConnectionString()))
            {
                using (System.Data.SqlClient.SqlCommand command = new System.Data.SqlClient.SqlCommand("newBehzad", conn) { CommandType = CommandType.StoredProcedure })
                {
                    conn.Open();
                    command.Parameters.Add("@id", SqlDbType.BigInt).Value = 2;
                    command.Parameters.Add("@ResultValue", SqlDbType.Int).Direction  = ParameterDirection.Output;

                    command.ExecuteNonQuery();

                    returnValue = command.Parameters["@ResultValue"].Value;

                    conn.Close();
                }
                if (returnValue != null)
                    MessageBox.Show(returnValue.ToString());
            }