ASP.NET实现根据URL生成网页缩略图的方法

来源：软文情感网

本文实例讲述了ASP.NET实现根据URL生成网页缩略图的方法。分享给大家供大家参考，具体如下：

工作中需要用到根据URL生成网页缩略图功能，提前做好准备。

在网上找了份源码，但是有错误:当前线程不在单线程单元中，因此无法实例化 ActiveX 控件“8856f961-340a-11d0-a9”，解决后运行良好，记录在此备用！

起始页：Default.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="CaptureToImage._Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
 <title>Snap</title>
</head>
<body>
 <form id="form1" runat="server">
 <div>
 <input type="button" onclick="window.open('Snap.aspx?url=www.njude.com.cn')" value="生成网页缩略图"/>
 </div>
 </form>
</body>
</html>

调用页：Snap.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Snap.aspx.cs" Inherits="CaptureToImage.Snap" AspCompat="true" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
 <title>无标题页</title>
</head>
<body>
 <form id="form1" runat="server">
 <div>
 </div>
 </form>
</body>
</html>

PS：红色字体部分是为解决错误增加的代码，强制程序在单线程环境下运行！

调用页：Snap.aspx.cs

using System;
using System.Data;
using System.Configuration;
using System.Collections;
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;
using System.Drawing.Imaging;
namespace CaptureToImage
{
 public partial class Snap : System.Web.UI.Page
 {
 protected void Page_Load(object sender, EventArgs e)
 {
 string url = string.Empty;
 url = Request.QueryString[0];
 try
 {
 GetImage thumb = new GetImage(url, 1024, 768, 800, 600);
 System.Drawing.Bitmap x = thumb.GetBitmap();
 x.Save(Response.OutputStream, ImageFormat.Jpeg);
 Response.ContentType = "image/jpeg";
 }
 catch (Exception ex)
 {
 Response.Write(ex.Message);
 }
 }
 }
}

类文件：GetImage.cs

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Windows.Forms;
using System.Web.UI;
namespace CaptureToImage
{
 public class GetImage
 {
 int S_Height;
 int S_Width;
 int F_Height;
 int F_Width;
 string MyURL;
 public int ScreenHeight
 {
 get
 {
 return S_Height;
 }
 set
 {
 S_Height = value;
 }
 }
 public int ScreenWidth
 {
 get
 {
 return S_Width;
 }
 set
 {
 S_Width = value;
 }
 }
 public int ImageHeight
 {
 get
 {
 return F_Height;
 }
 set
 {
 F_Height = value;
 }
 }
 public int ImageWidth
 {
 get
 {
 return F_Width;
 }
 set
 {
 F_Width = value;
 }
 }
 public string WebSite
 {
 get
 {
 return MyURL;
 }
 set
 {
 MyURL = value;
 }
 }
 public GetImage(string WebSite, int ScreenWidth, int ScreenHeight, int ImageWidth, int ImageHeight)
 {
 this.WebSite = WebSite;
 this.ScreenHeight = ScreenHeight;
 this.ScreenWidth = ScreenWidth;
 this.ImageHeight = ImageHeight;
 this.ImageWidth = ImageWidth;
 }
 [STAThread]
 public Bitmap GetBitmap()
 {
 WebPageBitmap Shot = new WebPageBitmap(this.WebSite, this.ScreenWidth, this.ScreenHeight);
 Shot.GetIt();
 Bitmap Pic = Shot.DrawBitmap(this.ImageHeight, this.ImageWidth);
 return Pic;
 }
 }
 public class WebPageBitmap
 {
 WebBrowser MyBrowser;
 string URL;
 int Height;
 int Width;
 public WebPageBitmap(string url, int width, int height)
 {
 this.URL = url;
 this.Width = width;
 this.Height = height;
 MyBrowser = new WebBrowser();
 MyBrowser.ScrollBarsEnabled = false;
 MyBrowser.Size = new Size(this.Width, this.Height);
 }
 public void GetIt()
 {
 NavigateUrl(this.URL);
 while (MyBrowser.ReadyState != WebBrowserReadyState.Complete)
 {
 Application.DoEvents();
 }
 }
 public delegate void DelUserHandler(string url);
 public void NavigateUrl(string url)
 {
 try
 {
 if (this.MyBrowser.InvokeRequired)
 {
 DelUserHandler handler = new DelUserHandler(NavigateUrl);
 MyBrowser.Invoke(handler, url);
 }
 else
 {
 this.MyBrowser.Navigate(url);
 }
 }
 catch (Exception ex)
 {
 throw new Exception("NavigateUrl()" + ex.Message);
 }
 }
 public Bitmap DrawBitmap(int theight, int twidth)
 {
 Bitmap myBitmap = new Bitmap(this.Width, this.Height);
 Rectangle DrawRect = new Rectangle(0, 0, this.Width, this.Height);
 MyBrowser.DrawToBitmap(myBitmap, DrawRect);
 System.Drawing.Image imgOutput = myBitmap;
 System.Drawing.Bitmap oThumbNail = new Bitmap(twidth, theight, imgOutput.PixelFormat);
 Graphics g = Graphics.FromImage(oThumbNail);
 g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighSpeed;
 g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighSpeed;
 g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBilinear;
 Rectangle oRectangle = new Rectangle(0, 0, twidth, theight);
 g.DrawImage(imgOutput, oRectangle);
 try
 {
 return oThumbNail;
 }
 catch
 {
 return null;
 }
 finally
 {
 imgOutput.Dispose();
 imgOutput = null;
 MyBrowser.Dispose();
 MyBrowser = null;
 }
 }
 }
}

PS：项目中需要添加引用System.Windows.Forms

希望本文所述对大家asp.net程序设计有所帮助。