怎么样在ASP.NET中实现根据URL生成网页缩略图？
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" 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。
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