存储过程 Id 设置为 Output！

存储过程：

ALTER PROCEDURE[dbo].[MAJ_Role_Save]
    -- Add the parameters for the stored procedure here
    @Id Bigint =0 OUTPUT,
    @RoleName nvarchar(50) =null,
    @TokenList nvarchar(max) = null,
    @CreateTime DateTime = null,
    @UpdateTime DateTime = null
AS
BEGIN
    IF @Id = 0
    BEGIN
        insert into dbo.MAJ_Role
    (
        RoleName ,
        TokenList,
        CreateTime,
        UpdateTime
    )
            values
    (
        @RoleName ,
        @TokenList,
        @CreateTime,
        @UpdateTime
    )
        -- Return Id
        SET @Id = SCOPE_IDENTITY();
    END
    ELSE
    BEGIN
        update dbo.MAJ_Role set
        RoleName = @RoleName ,
        TokenList = @TokenList,
        UpdateTime = @UpdateTime
        where Id = @Id
    END
END


测试代码：

  public static void Save(string roleName, string tokenList,DateTime createTime,DateTime updateTime)
    {
        string connString = System.Configuration.ConfigurationManager.ConnectionStrings["Sql"].ConnectionString;
        long Id = 0;
        using (TransactionScope scope = new TransactionScope())
        {
            using (SqlConnection conn = new SqlConnection(connString))
            {
                conn.Open();
                // Stored procedure
                SqlCommand cmd = new SqlCommand("dbo.MAJ_Role_Save", conn);
                = CommandType.StoredProcedure;
                cmd.Parameters.Add("@Id", SqlDbType.Int).Value = Id;
                cmd.Parameters.Add("@RoleName", SqlDbType.NVarChar, 50).Value = roleName;
                cmd.Parameters.Add("@TokenList", SqlDbType.NVarChar, 1000).Value = tokenList;
                cmd.Parameters.Add("@CreateTime", SqlDbType.DateTime).Value = createTime;
                cmd.Parameters.Add("@UpdateTime", SqlDbType.DateTime).Value = updateTime;



                //cmd.Parameters[@test].Direction = System.Data.ParameterDirection.ReturnValue;
                cmd.Parameters[0].Direction = System.Data.ParameterDirection.Output;


              
                int count = cmd.ExecuteNonQuery();
               
                conn.Close();

                Id = Convert.ToInt64(cmd.Parameters["@Id"].Value);
            

            }
            ();
        }

    Id = Convert.ToInt64(cmd.Parameters["@Id"].Value);//这句话 出错！ 存储过程没执行成功！没有数据插入！