在ASP.NET里轻松实现缩略图
<%
@ Page Language="C#" AutoEventWireup="true" CodeFile="Default5.aspx.cs" Inherits="Default5" %>
<!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" enctype="multipart/form-data">
<div>
<asp:Label id="Label1" runat="server"></asp:Label>
<INPUT type="file" name="file" width="600"><br><br>
<asp:FileUpload ID="FileUpload1" runat="server"/>
<asp:Button id="Button1" runat="server" OnClick="Button1_Click"></asp:Button>
</div>
</form>
</body>
</html>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.IO;
using System.Drawing.Imaging;
public partial class Default5 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
// 在此处放置用户代码以初始化页面
Label1.Text = "<h3>在ASP.NET里轻松实现缩略图</h3>";
Button1.Text = "上载并显示缩略图";
}
protected void Button1_Click(object sender, System.EventArgs e)
{
HttpFileCollection MyFileColl = HttpContext.Current.Request.Files;
//HttpPostedFile MyPostedFile = MyFileColl[0];
HttpPostedFile MyPostedFile = FileUpload1.PostedFile;
if (MyPostedFile.ContentType.ToString().ToLower().IndexOf("image") < 0)
{
Response.Write("无效的图形格式。");
return;
}
GetThumbNail(MyPostedFile.FileName, 100, 100,
MyPostedFile.ContentType.ToString(), false, MyPostedFile.InputStream);
}
private System.Drawing.Imaging.ImageFormat GetImageType(object strContentType)
{
if ((strContentType.ToString().ToLower()) == "image/pjpeg")
{
return System.Drawing.Imaging.ImageFormat.Jpeg;
}
else if ((strContentType.ToString().ToLower()) == "image/gif")
{
return System.Drawing.Imaging.ImageFormat.Gif;
}
else if ((strContentType.ToString().ToLower()) == "image/bmp")
{
return System.Drawing.Imaging.ImageFormat.Bmp;
}
else if ((strContentType.ToString().ToLower()) == "image/tiff")
{
return System.Drawing.Imaging.ImageFormat.Tiff;
}
else if ((strContentType.ToString().ToLower()) == "image/x-icon")
{
return System.Drawing.Imaging.ImageFormat.Icon;
}
else if ((strContentType.ToString().ToLower()) == "image/x-png")
{
return System.Drawing.Imaging.ImageFormat.Png;
}
else if ((strContentType.ToString().ToLower()) == "image/x-emf")
{
return System.Drawing.Imaging.ImageFormat.Emf;
}
else if ((strContentType.ToString().ToLower()) == "image/x-exif")
{
return System.Drawing.Imaging.ImageFormat.Exif;
}
else if ((strContentType.ToString().ToLower()) == "image/x-wmf")
{
return System.Drawing.Imaging.ImageFormat.Wmf;
}
else
{
return System.Drawing.Imaging.ImageFormat.MemoryBmp;
}
}
private void GetThumbNail(string strFileName, int iWidth, int iheight,
string strContentType, bool blnGetFromFile, System.IO.Stream ImgStream)
{
System.Drawing.Image oImg;
if (blnGetFromFile)
{
oImg = System.Drawing.Image.FromFile(strFileName);
}
else
{
oImg = System.Drawing.Image.FromStream(ImgStream);
}
oImg = oImg.GetThumbnailImage(iWidth, iheight, null, IntPtr.Zero);
string strGuid = System.Guid.NewGuid().ToString().ToUpper();
string strFileExt = strFileName.Substring(strFileName.LastIndexOf("."));
Response.ContentType = strContentType;
MemoryStream MemStream = new MemoryStream();
oImg.Save(MemStream, GetImageType(strContentType));
MemStream.WriteTo(Response.OutputStream);
}
}
