ASP.NET实现根据URL生成网页缩略图的方法

2024-07-10 13:29:39

字体：大中小

来源：转载

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这篇文章主要介绍了ASP.NET实现根据URL生成网页缩略图的方法,结合实例较为详细的分析了asp.net生成网页缩略图的详细实现技巧与相关注意事项,需要的朋友可以参考下

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;

}

}

}

}