在ASP.NET中上传图片并生成缩略图的C#源码

http://www.knowsky.com/5723.html

using System;

using System.Collections;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Web;

using System.Web.SessionState;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.HtmlControls;

using System.IO;

using System.Drawing.Imaging;

namespace eMeng.Exam

{

/// <summary>

/// Thumbnail 的摘要说明。

/// </summary>

public class Thumbnail : System.Web.UI.Page

{

protected System.Web.UI.WebControls.Label Label1;

protected System.Web.UI.WebControls.Button Button1;

private void Page_Load(object sender, System.EventArgs e)

{

// 在此处放置用户代码以初始化页面

Label1.Text = "<h3>在ASP.NET里轻松实炙趼酝?lt;/h3>";

Button1.Text = "上载并显示缩略图";

}

#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.Button1.Click += new System.EventHandler(this.Button1_Click);

this.Load += new System.EventHandler(this.Page_Load);

}

#endregion

private void Button1_Click(object sender, System.EventArgs e)

{

HttpFileCollection MyFileColl = HttpContext.Current.Request.Files;

HttpPostedFile MyPostedFile = MyFileColl[0];

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);

}

}

}

</FONT></FONT></FONT><FONT color=#ff0000 size=4></FONT><FONT size=4>功能：

1。把图片文件(JPG GIF PNG)上传，

2。保存到指定的路径（在web.config中设置路径，以文件的原有格式保存），

3。并自动生成指定宽度的（在web.config中设置宽度）

4。和指定格式的（在web.config中指定缩略图的格式）

5。和原图比例相同的缩略图(根据宽度和原图的宽和高计算所略图的高度)

6。可以判断是否已经存在文件

7。如果不覆盖，则给出错误

8。如果选中"覆盖原图"checkbox，则覆盖原图。

9。可以根据要求，在webform上设置1个以上的file input和相应的checkbox

10。并在文件上传完毕后，显示原图的文件名，尺寸，字节，和

11。缩略图的文件名尺寸。

12。缩略图的文件名格式：原图+"_thumb."+指定格式，如：test.jpg_thumb.gif,以便于管理。

--------------------

public void UploadFile(object sender, System.EventArgs e)

{

string imgNameOnly, imgNameNoExt, imgExt;

string imgThumbnail;

int erroNumber = 0;

System.Drawing.Image oriImg, newImg;

string strFePicSavePath = ConfigurationSettings.AppSettings["FePicSavePath"].ToString();

string strFePicThumbFormat = ConfigurationSettings.AppSettings["FePicThumbFormat"].ToString().ToLower();

int intFeThumbWidth = Int32.Parse(ConfigurationSettings.AppSettings["FePicThumbWidth"]);

string fileExt;

StringBuilder picInfo = new StringBuilder();

if(Page.IsValid)

{

for(int i = 0;i < Request.Files.Count; i++)

{

HttpPostedFile PostedFile = Request.Files[i];

fileExt = (System.IO.Path.GetExtension(PostedFile.FileName)).ToString().ToLower();

imgNameOnly = System.IO.Path.GetFileName(PostedFile.FileName);

if(fileExt == ".jpg" || fileExt == ".gif" || fileExt == ".png")

{

if(System.IO.File.Exists(strFePicSavePath + imgNameOnly) && (checkboxlistRewrite.Items[i].Selected == false))

{

erroNumber = erroNumber + 1;

picInfo.Append("<b>错误：</b>文件("+ (i+1) +") " + imgNameOnly + " 已经存在，请修改文件名<br/>" );

}

}

else

{

erroNumber = erroNumber + 1;

picInfo.Append("<b>错误：</b>文件("+ (i+1) +") " + imgNameOnly + " 扩展名 " + fileExt + " 不被许可<br/>" );

}

}

if(erroNumber > 0)

{

picInfo.Append("<font color=red>全部操作均未完成，请修改错误，再进行操作</font><br/>");

}

else

{

for(int i = 0;i < Request.Files.Count; i++)

{

HttpPostedFile PostedFile = Request.Files[i];

imgNameOnly = System.IO.Path.GetFileName(PostedFile.FileName);

imgNameNoExt = System.IO.Path.GetFileNameWithoutExtension(PostedFile.FileName);

imgExt = System.IO.Path.GetExtension(PostedFile.FileName).ToString().ToLower();

oriImg = System.Drawing.Image.FromStream(PostedFile.InputStream);

newImg = oriImg.GetThumbnailImage(intFeThumbWidth, intFeThumbWidth * oriImg.Height/oriImg.Width,null,new System.IntPtr(0));

switch(imgExt)

{

//case ".jpeg":

case ".jpg":

oriImg.Save(strFePicSavePath + imgNameOnly , System.Drawing.Imaging.ImageFormat.Jpeg);

break;

case ".gif":

oriImg.Save(strFePicSavePath + imgNameOnly , System.Drawing.Imaging.ImageFormat.Gif);

break;

case ".png":

oriImg.Save(strFePicSavePath + imgNameOnly , System.Drawing.Imaging.ImageFormat.Png);

break;

}

//oriImg.Save(ConfigurationSettings.AppSettings["FePicSavePath"] +
imgNameNoExt + ".jpg", System.Drawing.Imaging.ImageFormat.Jpeg);

switch(strFePicThumbFormat)

{

//jpeg format can get the smallest file size, and the png is the largest size

//case "jpeg":

case "jpg":

newImg.Save(strFePicSavePath + imgNameOnly + "_thumb.jpg",System.Drawing.Imaging.ImageFormat.Jpeg);

imgThumbnail = imgNameOnly + "_thumb.jpg";

break;

case "gif":

newImg.Save(strFePicSavePath + imgNameOnly + "_thumb.gif",System.Drawing.Imaging.ImageFormat.Gif);

imgThumbnail = imgNameOnly + "_thumb.gif";

break;

case "png":

newImg.Save(strFePicSavePath + imgNameOnly + "_thumb.png",System.Drawing.Imaging.ImageFormat.Png);

imgThumbnail = imgNameOnly + "_thumb.png";

break;

default:

newImg.Save(strFePicSavePath + imgNameOnly + "_thumb.jpg",System.Drawing.Imaging.ImageFormat.Jpeg);

imgThumbnail = imgNameOnly + "_thumb.jpg";

break;

}//switch

picInfo.Append("<b>文件　名：</b>" + imgNameOnly + " ( " +
oriImg.Width + " x " + oriImg.Height + " ) " +
PostedFile.ContentLength/1024 + "KB<br/>");

picInfo.Append("<b>
缩略图名：</b>" + imgThumbnail + " ( " + newImg.Width + " x " +
newImg.Height + " )<br/><br/>");

oriImg.Dispose();

newImg.Dispose();

}//for

picInfo.Append("<font color=red>所有操作成功</font><br/>");

}// if erronumber = 0

}

else

{

picInfo.Append("<font color=red>有错误，请检查。操作未成功</font><br/>");

}

lblPicInfo.Text = picInfo.ToString();

}