imagecode.aspx.cs

本程序只要配置好IIS就可以直接使用,是一个在线网上考试系统

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace exam
{
	/// <summary>
	/// imagecode 的摘要说明。
	/// </summary>
	public class imagecode : System.Web.UI.Page
	{
		private void Page_Load(object sender, System.EventArgs e)
		{
			this.CreateCheckCodeImage(RndNum()); 
		}

		private string RndNum() 
		{ 
			int number; 
			char code; 
			string checkCode = String.Empty; 

			System.Random random = new Random(); 

			for (int i = 0; i < 4; i++) 
			{ 
				number = random.Next(); 
				if (number % 2 == 0) 
					code = (char)('0' + (char)(number % 10)); 
				else 
					code = (char)('A' + (char)(number % 26)); 
				checkCode += code.ToString(); 
			} 
			Response.Cookies.Add(new HttpCookie("yzmcode", checkCode)); 
			return checkCode; 
		}

		private void CreateCheckCodeImage(string checkCode) 
		{ 
			if (checkCode == null || checkCode.Trim() == String.Empty) 
				return; 
			System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22); 
			Graphics g = Graphics.FromImage(image); 
			try 
			{ 
				//生成随机生成器 
				Random random = new Random(); 
				//清空图片背景色 
				g.Clear(Color.White); 
				//画图片的背景噪音线 
				for (int i = 0; i < 25; i++) 
				{ 
					int x1 = random.Next(image.Width); 
					int x2 = random.Next(image.Width); 
					int y1 = random.Next(image.Height); 
					int y2 = random.Next(image.Height); 
					g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2); 
				} 

				Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic)); 
				System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true); 
				g.DrawString(checkCode, font, brush, 2, 2); 
				//画图片的前景噪音点 
				for (int i = 0; i < 100; i++) 
				{ 
					int x = random.Next(image.Width); 
					int y = random.Next(image.Height); 
					image.SetPixel(x, y, Color.FromArgb(random.Next())); 
				} 
				//画图片的边框线 
				g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1); 
				System.IO.MemoryStream ms = new System.IO.MemoryStream(); 
				image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif); 
				Response.ClearContent(); 
				Response.ContentType = "image/Gif"; 
				Response.BinaryWrite(ms.ToArray()); 
			} 
			finally 
			{ 
				g.Dispose(); 
				image.Dispose(); 
			} 
		}

		#region Web 窗体设计器生成的代码
		override protected void OnInit(EventArgs e)
		{
			//
			// CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
			//
			InitializeComponent();
			base.OnInit(e);
		}
		
		/// <summary>
		/// 设计器支持所需的方法 - 不要使用代码编辑器修改
		/// 此方法的内容。
		/// </summary>
		private void InitializeComponent()
		{    
			this.Load += new System.EventHandler(this.Page_Load);

		}
		#endregion
	}
}