在插入行之后获取主键时出现InvalidCastException

Question

我正在使用以下查询来插入一行，我插入了行，但我希望获得主键以返回插入。行已成功插入，但获取主键给我带来了困难。一切顺利，但在lastID = Convert.ToInt32(Id.Value);它说InvalidCastException。问题“Getting primary key or any other attribute just after inserting a row”也与此问题有关

注意：主键列名是“Id”，它是int类型，我在asp.net中这样做

        SqlParameter Id =new SqlParameter("Id" , SqlDbType.Int);
        Id.Direction = ParameterDirection.Output;
        //conn.Open();
        //int inserted = 0;
        //int lastID = 0;
       string insertOffer = "INSERT INTO Offers (userId, column1, column2, column3)  
       VALUES (SomeINT, 'abc', 'abc', 'abc');select Id=SCOPE_IDENTITY()";
       int lastID = 0;
       using (SqlConnection conn = new SqlConnection(Connection))
       {
           conn.Open();
           using (SqlCommand comm = new SqlCommand(insertOffer, conn))
           {
               comm.Parameters.Add(Id);
               comm.ExecuteNonQuery();
               lastID = Convert.ToInt32(Id.Value);
           }//end using comm
       }//end using conn