C#循环结构应用实例-制作用户注册页面 推荐

代码如下：
[align=left]using System;[/align]
[align=left]using System.Collections.Generic;[/align]
[align=left]using System.Linq;[/align]
[align=left]using System.Web;[/align]
[align=left]using System.Web.UI;[/align]
[align=left]using System.Web.UI.WebControls;[/align]
[align=left]public partial class _Default : System.Web.UI.Page [/align]
[align=left]{[/align]
[align=left] protected void Page_Load(object sender, EventArgs e)[/align]
[align=left] {[/align]
[align=left] if(!IsPostBack ) //判断页面是否第一次加载[/align]
[align=left] {[/align]
[align=left] ViewState["biao"] = 0; //作为数组的下标[/align]
[align=left] ViewState["name"] = new string[3]; //用于存放“用户名”的数组[/align]
[align=left] ViewState["pawd"] = new string[3]; //用于存放“用户密码”的数组[/align]
[align=left] }[/align]
[align=left] [/align]
[align=left] }[/align]
[align=left] public int biao //定义“biao”为全局变量，并定义访问属性[/align]
[align=left] {[/align]
[align=left] get {return(int)ViewState ["biao"];}[/align]
[align=left] set { ViewState["biao"] = value; }[/align]
[align=left] }[/align]
[align=left] public string[] name //定义“name[]”为全局变量，并定义访问属性[/align]
[align=left] {[/align]
[align=left] get { return (string[])ViewState["name"]; }[/align]
[align=left] set { ViewState["name"] = value; }[/align]
[align=left] }[/align]
[align=left] public string[] pawd //定义“pawd[]”为全局变量，并定义访问属性[/align]
[align=left] {[/align]
[align=left] get { return (string[])ViewState["pawd"]; }[/align]
[align=left] set { ViewState["pawd"] = value; }[/align]
[align=left] }[/align]
[align=left] protected void Button1_Click(object sender, EventArgs e)[/align]
[align=left] {[/align]
[align=left] //用户注册按钮[/align]
[align=left] Label1.Text = "";[/align]
[align=left] Label2.Text = "";[/align]
[align=left] Label3.Text = "";[/align]
[align=left] int k=0;[/align]
[align=left] if(TextBox1 .Text !="")[/align]
[align=left] {[/align]
[align=left] for (int i = 0; i < name.Length;i++ )[/align]
[align=left] {[/align]
[align=left] if (name [i]==TextBox1 .Text ) //判断注册的用户是否已存在[/align]
[align=left] {[/align]
[align=left] k++;[/align]
[align=left] break;[/align]
[align=left] }[/align]
[align=left] [/align]
[align=left] }[/align]
[align=left] if (k == 0) [/align]
[align=left] {[/align]
[align=left] if (TextBox2.Text != "")[/align]
[align=left] {[/align]
[align=left] if (biao < name.Length) //判断下标是否超出数组范围[/align]
[align=left] {[/align]
[align=left] name[biao] = TextBox1.Text;[/align]
[align=left] pawd[biao] = TextBox2.Text;[/align]
[align=left] biao++;[/align]
[align=left] Label3.Text = "用户注册成功！！";[/align]
[align=left] }[/align]
[align=left] else[/align]
[align=left] {[/align]
[align=left] Label3.Text = "呵呵！不能注册了";[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] else[/align]
[align=left] {[/align]
[align=left] Label2.Text = "请输入密码！！";[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] else [/align]
[align=left] {[/align]
[align=left] Label3.Text = "用户已经存在！！";[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] else [/align]
[align=left] {[/align]
[align=left] Label1.Text = "请输入用户名！！";[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] protected void Button2_Click(object sender, EventArgs e)[/align]
[align=left] {[/align]
[align=left] //用户登录按钮[/align]
[align=left] Label1.Text = "";[/align]
[align=left] Label2.Text = "";[/align]
[align=left] Label3.Text = "";[/align]
[align=left] if (TextBox1.Text !="")[/align]
[align=left] {[/align]
[align=left] for (int i = 0; i < name.Length;i++ )[/align]
[align=left] {[/align]
[align=left] if (name[i] == TextBox1.Text) //判断登录用户是否在数组中存在[/align]
[align=left] {[/align]
[align=left] if (pawd[i] == TextBox2.Text) //判断登录用户密码是否在数组中存在[/align]
[align=left] {[/align]
[align=left] Label3.Text = "用户登录成功！！";[/align]
[align=left] }[/align]
[align=left] else[/align]
[align=left] {[/align]
[align=left] Label3.Text = "用户密码不正确！！";[/align]
[align=left] } [/align]
[align=left] break; [/align]
[align=left] }[/align]
[align=left] else[/align]
[align=left] {[/align]
[align=left] Label3.Text = "用户名不存在！！";[/align]
[align=left] }[/align]
[align=left] [/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] else [/align]
[align=left] {[/align]
[align=left] Label1.Text = "请输入用户名！！";[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] protected void Button3_Click(object sender, EventArgs e)[/align]
[align=left] {[/align]
[align=left] //显示所有用户按钮[/align]
[align=left] Label1.Text = "";[/align]
[align=left] Label2.Text = "";[/align]
[align=left] Label3.Text = "";[/align]
[align=left] for (int i = 0; i < name.Length; i++)[/align]
[align=left] {[/align]
[align=left] Label3.Text += name [i ]+ "　";[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] protected void Button4_Click(object sender, EventArgs e)[/align]
[align=left] {[/align]
[align=left] name=new string [3] ;[/align]
[align=left] pawd = new string[3]; //删除所有用户和密码[/align]
[align=left] }[/align]
[align=left] protected void Button5_Click(object sender, EventArgs e)[/align]
[align=left] {[/align]
[align=left] Label3.Text = ""; //清除显示内容[/align]
[align=left] }[/align]
[align=left] protected void Button6_Click(object sender, EventArgs e)[/align]
[align=left] {[/align]
[align=left] //显示用户名和密码[/align]
[align=left] if (TextBox1.Text == "admin") //判断查看用户和密码的当前用户[/align]
[align=left] {[/align]
[align=left] Label3.Text = "";[/align]
[align=left] for (int i = 0; i < name.Length; i++)[/align]
[align=left] {[/align]
[align=left] if (name [i ]!=null )[/align]
[align=left] {[/align]
[align=left] Label3.Text += "用户名：" + name[i] + "　" + "密码：" + pawd[i] + "</br>";[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] else[/align]
[align=left] {[/align]
[align=left] Label3.Text = "您没有权限查看！！";[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left]}[/align]
效果如下图：