image.aspx.cs

投票系统模块设计

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.IO;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using Common;

namespace book07
{
	/// <summary>
	/// Image 的摘要说明。
	/// </summary>
	public class Image : System.Web.UI.Page
	{
		private IPageCounter counter = null;
		//		private DbPageCounter counter = new DbPageCounter();
		//		private XmlPageCounter counter = new XmlPageCounter();
		private void Page_Load(object sender, System.EventArgs e)
		{
			counter = PageCounterManager.CreatePageCounter() as IPageCounter;
			CreateImage();
		}

		#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

		private void CreateImage()
		{
			string strPageCount = counter.GetPageCount().ToString();
			//			string strPageCount = Application["PageCount"].ToString();
			//若Application为空，则直接返回
			if(strPageCount == null || strPageCount.Trim() == String.Empty)
				return;

			//根据字符串的长度确定输出图片的长度
			System.Drawing.Bitmap image = new System.Drawing.Bitmap(
				(int)Math.Ceiling((strPageCount.Length * 15)), 20);

			//创建Graphics对象
			Graphics g = Graphics.FromImage(image);

			try
			{

				//输出图片中校验码的字体: 12号Arial,粗斜体
				Font font = new Font(
					"Arial",
					12,
					(FontStyle.Bold | FontStyle.Italic) );

				//线性渐变画刷
				LinearGradientBrush brush = new LinearGradientBrush(
					new Rectangle(0, 0, image.Width, image.Height),
					Color.Blue,
					Color.Purple,
					1.2f,
					true );
				g.DrawString(strPageCount, font, brush, 2, 2);

				//画图片的边框线
				g.DrawRectangle(
					new Pen(Color.SaddleBrown),
					0,
					0,
					image.Width - 1,
					image.Height - 1 );

				//创建内存流用于输出图片
				using (MemoryStream ms = new MemoryStream())
				{
					//图片格式指定为png
					image.Save(ms, ImageFormat.Png);

					//清除缓冲区流中的所有输出
					Response.ClearContent();

					//输出流的HTTP MIME类型设置为"image/Png"
					Response.ContentType = "image/Png";

					//输出图片的二进制流
					Response.BinaryWrite(ms.ToArray());
				}
			}
			finally
			{
				//释放Bitmap对象和Graphics对象
				g.Dispose();
				image.Dispose();				
			}

		}
	}
}