循环结构

第三章        循环结构

 

案例一：显示1至12月份

 

  Label1.Text = "";

        for (int i = 1; i <= 12; i++)

        {

        }

 

            Label1.Text += i + " 月&nbsp;&nbsp;" ;

 

 

案例二：显示鲜花分类

 

 

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

 

public partial class _Default : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

 

    }

    protected void Button1_Click(object sender, EventArgs e)

    {

        Label1.Text = "";// 创建保存鲜花分类列表的字符串型数组

        string[] flower = { " 红玫瑰" , " 百合" , " 蓝色妖姬" , " 康乃馨" , " 手提花篮" };

        string[] str= {"rose.aspx","lily.aspx","blue.aspx","carnation.aspx","basker.aspx"};

     for (int i=0; i<flower.Length; i++)// 使用for循环显示列表

     {

         Label1.Text+="<a href="+str[i]+">"+flower[i]+"</a><br/>";

     }

      

    }

}

 

 

案例三：显示日记

后台代码编写：

        if (!IsPostBack)

        {

            ViewState["index"] = 0;

            ViewState["riji"] = new string[31];

        }

    }

    public string[] riji

    {

        get { return (string[])ViewState["riji"]; }

        set { ViewState["riji"] = value; }

    }

    public int index

    {

        get { return (int)ViewState["index"]; }

        set { ViewState["index"] = value; }

 

    protected void Button1_Click(object sender, EventArgs e)

 

        Label1.Text = "";

        if (TextBox1.Text != "")

        {

            if (index < riji.Length)

            {

                riji[index] = " 时间： " + DateTime.Now.ToString() + "&nbsp;&nbsp;&nbsp;&nbsp;" +" 日记内容是： " + TextBox1.Text;

                index++;

                Label1.Text = " 添加日记成功 !";

                TextBox1.Text = "";

            }

            else

            {

                Label1.Text = " 一个月最多有 31 天 ";

            }

        }

        else

    {

            Label1.Text = " 请输入日记内容 ";

 

    protected void Button2_Click(object sender, EventArgs e)

 

        Label1.Text = "";

        foreach (string xianshi in riji)

        {

            if (xianshi != null)

            {

                Label1.Text = Label1.Text + xianshi +  "</br>";

            }

        }

    }

 

 

 

 

 

 

 

 

（3）进行验证：

点击添加日记，添加成功！

 

点击显示日记，显示成功！

 

点击清空显示，清空成功！

 

如果点击重写日记，那将会删除以前写过的日记：

 

案例四： 循环的中断

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

 

public partial class _Default : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

 

    }

    protected void Button1_Click(object sender, EventArgs e)

    {

        int i = 0;

        while (i < 100)// 循环i<100的数

        {

            if (i == 16)// 判断当i等于16时

                break;// 中断循环

            Label1.Text += Convert.ToString(i) + "&nbsp;&nbsp;";

            i++;

        }

    }

}

 

案例五：查询中奖号码

 

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

 

public partial class _Default : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

 

    }

    protected void Button1_Click(object sender, EventArgs e)

    {

        Label1.Text = " 本注彩票号码为：" ;

        Label2.Text = " 本期中奖号码为：" ;

        int[] num = { 3, 7, 19, 25, 27, 30, 33 };// 彩票的号码

        int[] win = { 3, 22, 66, 25, 90, 30, 33 }; // 中将的号码

        int k = 0; // 计算中奖 号码个数计数器

        int m = 0; // 彩票的号码

        int n = 0; // 中将的号码

        while (m < num.Length)

        {

            Label1.Text += num[m] + "&nbsp;&nbsp;";

            m++;

        }

        while (n < win.Length)

        {

            Label2.Text += win[n] +"&nbsp;&nbsp;";

            n++;

        }

        for (int i = 0; i < num.Length; i++)

        {

            for (int j = 0; j < win.Length; j++)

            {

                if (num[i] == win[j])

                {

                    k++;

                }

             

            }

        }

 

        switch (k)

        {

            case 7:

            TextBox1 .Text  = " 恭喜你！中了一个笔记本" ;

                break ;  

            case 6:

          TextBox1 .Text  = " 恭喜你中了一个手机" ;

                break ;   

            case 5:

            TextBox1 .Text  = " 恭喜你中了一个MP3" ;

                break ;       

            case 4:

            TextBox1 .Text  = " 恭喜你中了一个U盘" ;

                break ;

            default :   

        TextBox1 .Text  = " 恭喜你什么都没中" ;

         break;

       

        }

      

    }

}

 

 

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