编译器告诉我“；无法隐式转换类型'；char'；到'；bool'；

控制台告诉我，在（28,22），它"无法将类型‘char’隐式转换为‘bool’"，但在那个位置，我使用的是一个char变量，而不是试图将其转换为bool。代码中的这个位置else if（ch2='c'）确切的位置在"（"answers"c"之间。提前感谢您的帮助！

using System;
public class EntranceChecking
{
    public static void Main()
    {
        char ch1, ch2;// Input character
        bool guess = false; // Flag that signals when the loop should terminate --
        //   that is, when 'c' followed by 's' has been input.
        Console.WriteLine("'nYou have before you a closed door.");
        Console.WriteLine("You must give the correct password to enter");
        Console.WriteLine("Enter a character : ");
        ch1 = Console.ReadKey().KeyChar;

        // Insert a loop that keeps reading and processing characters
        // until the user inputs the character 'c' followed by the
        // character 's' (if ever).
         while (!guess)
        {
            Console.WriteLine("Enter a character : ");
            ch2 = Console.ReadKey().KeyChar;
            if ((ch1 == 'c') && (ch2 == 's'))
                guess = true;
            else if (ch2 = 'c')
            {
                ch1 = 'c';
                break;
            }
            else
                ch1 = Console.ReadKey().KeyChar;
        }
        // Open the door.
        Console.Write("The door opens. Congratulations!");
    }
}

else if (ch2 = 'c')

else if (ch2 == 'c')