Using the fileupload control upload images and automatically generate thumbnails

This article implements the upload of the picture file by means of the fileupload control in VS2005 and generates a thumbnail.

Implementation process: After selecting the image upload success, obtain the file that already exists in the existing server generates thumbnails, and determines whether it is a picture type file, this judgment can be modified in the program, this program is just judging "image / bmp", "image / gif "," image / pjpeg "three types.

code show as below:

Upfile.aspx file

<%

@ Page language = "c #" autoeventwireup = "true" codefile = "upfile.aspx.cs" inherits = "upfile_upfile"

%>

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

>

Untitled Page

Title

>

HEAD

>

<

Body

>

<

FORM

id

= "Form1"

Runat

= "Server"

>

<

Div

>

<

ASP: FileUpload

Id

= "FileUpload1"

Runat

= "Server"

/>

<

ASP: Button

Id

= "Button1"

Runat

= "Server"

Onclick

= "Button1_click"

TEXT

= "Upload"

/> <

Br

/>

<

ASP: Label

Id

= "Label1"

Runat

= "Server"

>

ASP: Label

>

Div

>

FORM

>

Body

>

HTML

>

Upfile.aspx.cs file

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;

public

Partial

Class

Upfile_upfile: system.Web.ui.page

{Protected void Page_Load (object sender, EventArgs e) {} protected void Button1_Click (object sender, EventArgs e) {if (FileUpload1.HasFile) {string fileContentType = FileUpload1.PostedFile.ContentType; if (fileContentType == "image / bmp" || fileContentType == "image / gif" || fileContentType == "image / pjpeg") {string name = FileUpload1.PostedFile.FileName; // client file path FileInfo file = new FileInfo (name); string fileName = file .Name; // file name string filename_s = "s_" file.name; // thumbnail file name string WebFilePath = Server.mappath ("file /" filename); // server-side file path string WebFilePath_s = Server. Mappath ("file /" filename_s); // server-side thumbnail path if (! File.exists (webfilepath)) {TRY { FILEUPLOAD1.SAVEAS (WebFilePath); // Save File MakethumbNail (WebFilePath, WebFilePath_s, 130, 130, "CUT"); // Generate Thumbnail Method Label1.Text = "Tip: File" FileName "" Successfully uploaded, and generated " filename_s " thumbnail, file type: " fileupload1.postedfile.contentType ", file size is: " fileupload1.postedFile.contentLength " B ";} catch (Exception EX) ) {Label1.text = "

Tip: Document Upload Failure, Failure Cause: " EX.MESSAGE;}} Else {Label1.Text =" Tip: The file already exists, please rename ";}} else {label1.text =" Tip: File type Do not match ";}}} / ** ////

/// generated thumbnail /// /// Source diagram path (physical path) /// Thumbnail path (physical path) /// thumbnail width /// Thumbnail height /// Generate thumbnail public static void makethumbnail (String OriginalImagePath, String thumbnailpath, int width, int hotht, string mode) { System.Drawing.Image originalImage = System.Drawing.Image.FromFile (originalImagePath); int towidth = width; int toheight = height; int x = 0; int y = 0; int ow = originalImage.Width; int oh = originalImage. HEIGHT; SWITCH (Mode) { Case "hw": / / Specify high width zoom (possible deformation) Break; case "w": // Specify wide, high proportion toHeight = OriginalImage.Height * width / OriginalImage.width; Break; Case "H": / / Specify high, broadly proportional toidth = OriginalImage.width * height / originalimage.height; break; case "cut": // Specify high wide cut (not deformation)

if ((double) originalImage.Width / (double) originalImage.Height> (double) towidth / (double) toheight) {oh = originalImage.Height; ow = originalImage.Height * towidth / toheight; y = 0; x = ( OriginalImage.width - OW) / 2;} else {OW = OriginalImage.Width; OH = OriginalImage.width * Height / Towidth; x = 0; Y = (OriginalImage.Height - OH) / 2;} Break; Default: BREAK ;} // Create a bmp picture System.Drawing.Image bitmap = new System.Drawing.Bitmap (towidth, toheight); // Create a artboards System.Drawing.Graphics g = System.Drawing.Graphics.FromImage (bitmap); // Set high quality interpolation g.interpolationmode = system.drawing.drawing2d.interpolationmode.high; // Set high quality, low speed rendering smoothing degree g.smoothingMode = system.draw ing.drawing2d.smoothingmode.highquality; // Empty canvas and populate g.clear (system.drawing.color.transparent) in transparent background; // Draw the specified section of the original picture in the specified position and press the specified size G.DrawImage OriginalImage, New System.drawing.Rectangle (0, 0, Towidth, Toheight), New System.drawing.Rectangle (X, Y, OW, OH), System.drawing.graphicsUnit.pixel; try {// Taking JPG format Save thumbnail Bitmap.Save (thumbnailpath, system.drawing.imaging.imageformat.jpeg);} catch (system.exception e) {throw e;} finally {OriginalImage.dispose (); bitmap.dispose (); g.dispose ();