最近参加了Web基础开发的培训，收获不少，做了一个练习，在后台动态创建控件制作了一个简单功能的计算器。程序中控件创建好以后，往往不能放在想要的位置，前台的布局非常麻烦，我用Table、TableRow、TableCell对象来帮助前台页面的布局。在创建控件前，将要创建的控件分类，按照分类，用重载的方法自己定义了CreateBtn函数。然后用循环调用的方法进行创建。整个程序的代码如下：
前台HTML代码（VS2005自动生成的，我没做任何修改）；
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server"> <title>网页动态生成计算器</title></head><body> <form id="form1" runat="server"> <div> </div> </form></body></html>后台Ａｓｐ．ｎｅｔ代码：
using System;using System.Data;using System.Configuration;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;public partial class _Default : System.Web.UI.Page {
//定义两个操作数 static double Num1; static double Num2; //记录操作符 static string OperatorF; //判断“=”是否被点击过，每次操作时清空上次操作的记录 static bool ReOperator = false; TextBox txtShow = new TextBox(); 
/// <summary>
/// 在页面登录事件里面创建计算器的界面 /// </summary> /// <param name="sender"></param>
/// <param name="e"></param> protected void Page_Load(object sender, EventArgs e) { //定义表格用于容纳其它创建的控件 Table txtTB = new Table(); form1.Controls.Add(txtTB); txtShow.Width = 110; TableRow TR = new TableRow(); TableCell TC = new TableCell(); TC.Controls.Add(txtShow); TR.Controls.Add(TC); txtTB.Controls.Add(TR); Table TB = new Table(); form1.Controls.Add(TB); //循环创建有规律分布的数字控件，和操作符控件 for (int i = 0,I = 1; i < 3; i++) { //用两个数组记录操作符控件的Text和ID值 string[] Op = {"+","-","*"}; string[] CharOp = {"jia","jian","cheng"}; TableRow TRows = new TableRow(); TB.Controls.Add(TRows); for (int j = 0; j < 3; j++) { TableCell Tcell = new TableCell(); Tcell.Controls.Add(CreateBtn(I.ToString())); I++; TRows.Controls.Add(Tcell); } TableCell TcellO = new TableCell(); Button OperBtn = new Button(); OperBtn.Text = Op[i]; OperBtn.ID = CharOp[i]; OperBtn.Width = 25; OperBtn.Click += new EventHandler(Btn_Click); TcellO.Controls.Add(OperBtn); TRows.Controls.Add(TcellO); } TableRow TRow = new TableRow(); TB.Controls.Add(TRow); TableCell Tc2 = new TableCell(); Tc2.Controls.Add(CreateBtn("Backspace","B")); TRow.Controls.Add(Tc2); TableCell Tc3 = new TableCell(); Tc3.Controls.Add(CreateBtn("Clear","C")); TRow.Controls.Add(Tc3); TableCell Tc1 = new TableCell(); Tc1.Controls.Add(CreateBtn("deng", "=")); TRow.Controls.Add(Tc1); TableCell Tc = new TableCell(); Tc.Controls.Add(CreateBtn("chu", "/")); TRow.Controls.Add(Tc); } /// <summary> /// 创建操作数按钮的函数 /// </summary> /// <param name="Num">操作数</param> /// <returns>返回一个按钮</returns> protected Button CreateBtn(string Num) { Button NumBtn = new Button(); NumBtn.Text = Num; NumBtn.ID = "ID" + Num; NumBtn.Width = 25; NumBtn.Click += new EventHandler(Btn_Click); return NumBtn; } /// <summary> /// 创建操作符按钮的函数 /// </summary> /// <param name="ID">按钮的ID号</param> /// <param name="Operator">操作符</param> /// <returns>返回一个按钮</returns> private Button CreateBtn(string ID, string Operator) { Button OperBtn = new Button(); OperBtn.Text = Operator; OperBtn.ID = ID; OperBtn.Width = 25; OperBtn.Click += new EventHandler(Btn_Click); return OperBtn; } /// <summary> /// 定义按钮响应的事件，所有按钮通用一个事件，用按钮的Text属性区分要执行的操作 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void Btn_Click(object sender, EventArgs e) { string BtnText = ((Button)sender).Text; switch(BtnText) { case "+": Num1 = int.Parse(txtShow.Text); OperatorF = BtnText; txtShow.Text = ""; break; case "-": Num1 = int.Parse(txtShow.Text); OperatorF = BtnText; txtShow.Text = ""; break; case "*": Num1 = int.Parse(txtShow.Text); OperatorF = BtnText; txtShow.Text = ""; break; case "/": Num1 = int.Parse(txtShow.Text); OperatorF = BtnText; txtShow.Text = ""; break; case "=": if (OperatorF == "+") { Num2 = Num1 + double.Parse(txtShow.Text); txtShow.Text = Num2.ToString(); } else if (OperatorF == "-") { Num2 = Num1 - double.Parse(txtShow.Text); txtShow.Text = Num2.ToString(); } else if (OperatorF == "*") { Num2 = Num1 * double.Parse(txtShow.Text); txtShow.Text = Num2.ToString(); } else if (OperatorF == "/") { Num2 = Num1 / double.Parse(txtShow.Text); txtShow.Text = Num2.ToString(); } ReOperator = true; break; case "C": txtShow.Text = ""; Num1 = Num2 = 0; break; case "B": if (txtShow.Text.Length >=1) { txtShow.Text = txtShow.Text.Substring(0, txtShow.Text.Length - 1); if (txtShow.Text != "") Num1 = int.Parse(txtShow.Text); else Num1 = 0; } break; default: if (ReOperator) { txtShow.Text = ""; Num1 = Num2 = 0; ReOperator = false; } txtShow.Text += BtnText; break; } } 
}整个程序的运行结果如下：
可以将这个计算器做成一个自定义Web控件，代码的改动不大，以后有机会了再讲，程序中做的计算器的功能还不完整，有的地方控制还不够，广大网友有兴趣还可以自己完善扩展。
