关于IF的问题

请帮我看一下，这个代码为什么不能判断年龄using System ;class zhao{ private string xingming; private string xingbie; private int nianling; public string Xingming { get {return xingming;} set {xingming=value;} } public string Xingbie { get {return xingbie;} set { if (value=="男"||value=="女") { xingbie=value; } else { Console.WriteLine("性别只能为男或女"); } } } public int Nianling { get {return nianling;} set { if (value<50||value>8) { nianling=value; } else { Console.WriteLine ("只能大于8或小于50"); } } }} class b { static void Main() { zhao z=new zhao(); z.Xingming="张三"; z.Xingbie="男"; z.Nianling=72; Console.WriteLine(z.Xingming ); Console.WriteLine(z.Xingbie ); Console.WriteLine(z.Nianling ); } }