用C#写的一个课后练习,影院售票系统,写完有一行报错了我没理解,望请教!

这是整个上下文,报错的地方在语句if{check="Y}那里,报错的提示我没理解,这是一个练习,希望指点一下错误的问题在哪

img

 int[,] tickets = new int[4, 5];
            //给二维数组的每一个元素赋值,均为1,表示该行和列对应的座位有票
            for (int i = 0; i < tickets.GetLength(0); i++)
            {
                for (int j = 0; j < tickets.GetLength(1); j++)
                {
                    tickets[i, j] = 1;
                }
            }
            //把座位上的票打出来
            for (int i = 0; i < tickets.GetLength(0); i++)
            {
                for (int j = 0; j < tickets.GetLength(1); j++)
                {
                    Console.Write(tickets[i,j]+" ");
                }
                Console.WriteLine();
            }
            Console.WriteLine("欢迎进入售票系统");
            
            while (true)
            {
                Console.WriteLine("B-购买 C-查询 Q-退出");
                string input = Console.ReadLine();
                if (input=="B")
                {
                    Console.WriteLine("请输入行号和列号:1-4");
                    int hang = Convert.ToInt32(Console.ReadLine());
                    Console.WriteLine("请输入列号:1-5");
                    int lie = Convert.ToInt32(Console.ReadLine());
                    if (tickets[hang-1,lie-1]==0)
                    {
                        Console.WriteLine("该座位没票");
                    }
                    else
                    {
                        Console.WriteLine("Y-确认购买 N-返回主界面");
                        string check = Console.ReadLine();
                        if (check == "Y")
                        {    //这里开始提示报错了
                            tickets[hang - 1, lie - 1] == 0;
                            Console.WriteLine("购买成功,你的座位在第{0}行,第{1}列",hang,lie);
                            
                        }
                    }
                }
                else if (input == "C")
                {
                    Console.WriteLine("A-查询全部 P-查询单个");
                    string sele = Console.ReadLine();
                    if (sele=="A")
                    {
                        for (int i = 0; i < tickets.GetLength(0); i++)
                        {
                            for (int j = 0; j < tickets.GetLength(1); j++)
                            {
                                Console.Write(tickets[i, j] + " ");
                            }
                            Console.WriteLine();
                        }
                    }
                    if(sele == "P")
                    {
                        Console.WriteLine("请输入要查询的行");
                        int hang = Convert.ToInt32(Console.ReadLine());
                        Console.WriteLine("请输入要查询的列");
                        int lie = Convert.ToInt32(Console.ReadLine());
                        if (tickets[hang - 1, lie - 1] == 1)
                        {
                            Console.WriteLine("该座位有票");
                        }
                        else
                        {
                            Console.WriteLine("该座位没票");
                        }
                    }
                }
                else
                {
                    Console.WriteLine("welcome next come in");
                    break;
                }
            }

tickets[hang - 1, lie - 1] == 0;
改为
tickets[hang - 1, lie - 1] = 0;