csharp修饰符

文档位置

• https://docs.microsoft.com/zh-cn/dotnet/csharp/
• https://www.runoob.com/csharp/csharp-methods.html
• https://www.cjavapy.com/

out修饰符

public void OutFunc()
        {
            int n;
            bool b = MyTryParse("123", out n);
            Console.WriteLine(b);
            Console.WriteLine(n);
             
        }

        public static bool MyTryParse(string s, out int result)
        {
            result = 0;
            try
            {
                result = Convert.ToInt32(s);
                return true;
            }
            catch
            {
                return false;
            }
        }

Person p = new Teacher(); •子类可以隐式的转换成父类. Teacher t=(Teacher)p;

is和as

– typeA is type B 仅判断 – typeA as TypeB先判断,再转换 – 如果成功了那就是真的成功了,如果不成功返回空 – as 也是转换,但是 如果转换不了的 不报异常,返回来的是null – is 转换 ,返回的是bool值,true就是能转换,false 就是不能转换