注意Switch case 语句，case中的条件必须是constant value

case 中的条件必须是常量，而不能是变量，否则会报异常：“错误 1 A constant value is expected 。。。。”

 

        int a = 3;
        int b = 4;
        private void test(int c)
        {
            switch (c)
            {
                case a:
                    break;
                case b:
                    break;
                default:
                    break;
            }

        }

这种情况下会报异常。应该修改为：

       private void test(int c)
        {
            switch (c)
            {
                case 1:
                    break;
                case 2:
                    break;
                default:
                    break;
            }

        }