Question

C#如何判断整形变量不为空

Answer 1

用int?来定义整型。

using System;

namespace ConsoleApplication15
{
    class Program
    {
        static void Main(string[] args)
        {
            int? x = null;

             // 判断是否为空   
            if (!x.HasValue)
            {
                Console.WriteLine("x为空");
            }

            x = 100;
            // 判断是否有值
            if (x.HasValue)
            {
                Console.WriteLine(x);
            }

        }
    }
}