C# 中定义扩展方法

1.编写扩展方法类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace CSharpCharacteric
{
    /// <summary>
    /// 扩展方法类
    /// </summary>
    public static class Extension
    {
        /// <summary>
        /// 去除字符串中的空格
        /// </summary>
        /// <param name="data">字符串数据</param>
        public static string NoSpaces(this string data)
        {
            return data.Replace(" ","");
        }
        /// <summary>
        /// 将字符串转化为数字
        /// </summary>
        /// <param name="data">字符串</param>
        /// <returns>转换结果，如不能转换则返回0</returns>
        public static int ToInt(this string data)
        {
            int result=0;
            Int32.TryParse(data,out result);
            return result;
        }
    }
}

2.编写入口类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace CSharpCharacteric
{
    /// <summary>
    /// 入口类
    /// </summary>
    public class Program
    {
        /// <summary>
        /// 入口方法
        /// </summary>
        /// <param name="args"></param>
        public static void Main(string[] args)
        {
            string data = "This is my computer.";
            string afterString=data.NoSpaces();
            Console.WriteLine(afterString);
            Console.WriteLine("1234".ToInt());
            Console.WriteLine("12.3".ToInt());
            Console.WriteLine("abc".ToInt());
        }
    }
}