为什么"；写“；函数不'；我第一时间不工作

At result write函数不适用于"8"，但它可以写入7,6,5，。。。分别地当我跟踪代码时，我找不到任何错误。。。（代码必须用数字绘制棋盘）

Console.ForegroundColor = ConsoleColor.Yellow;
        Console.WriteLine("   a   b   c   d   e   f   g   h");
        Console.BackgroundColor = ConsoleColor.Blue;
        Console.Write(" ╔═══╦═══╦═══╦═══╦═══╦═══╦═══╦═══╗'n");
        Console.ForegroundColor = ConsoleColor.Blue;
        for (int i = 7; i > -1;i--)
        {
            Console.Write((i + 1).ToString());//Problem is here
            for (int j=0;j<8;j++)
            {
                Console.ForegroundColor = ConsoleColor.Yellow;
                Console.BackgroundColor = ConsoleColor.Blue;
                Console.Write("║");
                if(i%2!=0)
                {
                    if(j%2==0)
                    {
                        Console.BackgroundColor = ConsoleColor.White;
                    }
                    else
                    {
                        Console.BackgroundColor = ConsoleColor.Black;
                    }
                }
                else
                {
                    if (j % 2 == 0)
                    {
                        Console.BackgroundColor = ConsoleColor.Black;
                    }
                    else
                    {
                        Console.BackgroundColor = ConsoleColor.White;
                    }
                }
                Console.Write(" "+ch[i,j].ToString()+" ");
            }
            Console.BackgroundColor = ConsoleColor.Blue;
            Console.Write("║'n");
            if(i!=0)
            {
                Console.WriteLine(" ╠═══╬═══╬═══╬═══╬═══╬═══╬═══╬═══╣");
            }
            else
            {
                Console.WriteLine(" ╚═══╩═══╩═══╩═══╩═══╩═══╩═══╩═══╝");
            }
        }