1.系统类的扩展方法
//帮助类标记为static
???public static class StringHelper
???{
???????//扩展的方法也要标记为静态的
???????public static bool IsEmail(this string str)//this要紧跟扩展的类型
???????{
???????????bool result = true;
???????????if (!str.Contains("@"))
???????????{
???????????????result = false;
???????????}
???????????return result;
???????}
???????public static string BoolToString(this bool b)
???????{
???????????string str = string.Empty;
???????????if (b)
???????????{
??????????????str="真";
???????????}
???????????else
???????????{
???????????????str = "假";
???????????}
???????????return str;
???????}
public static string BbQuote(this string str, string pre, string tag)
???????{
???????????return pre + str + tag;
???????}
???}
调用扩展的方法：
public partial class Form1 : Form
???{
???????public Form1()
???????{
???????????InitializeComponent();
???????}
???????private void button1_Click(object sender, EventArgs e)
???????{
???????????string email = "123@qq.com";
???????????bool b = email.IsEmail();
???????????string msg= b.BoolToString();
???????????MessageBox.Show(msg);
???????????MessageBox.Show(email.BbQuote("_","|"));
???????}
???}
.Net高级技术：Linq
原文地址：https://www.cnblogs.com/francis-ray/p/10161155.html