Webform (File upload)

1.HTML Encoding:

<type= "file"/>

2. Control: FileUpload

It is used to select files to upload, and a button is required to upload the selected files to the server

String path = "images/" + fileupload1.filename;
Fileupload1.saveas (Server.MapPath (path));

Optimization 1: The file retains its original name and suffix

String path = "images/" + fileupload1.filename;

Optimization 2: Prevent duplicate names, or multiple people at the same time upload the same name file

String path = "images/" + DateTime.Now.ToString ("Yyyymmddhhssmmms") + request.cookies["Ures"]. Value + fileupload1.filename;

Optimization 3: Can upload large files, default is 4MB,4096KB
Method: Expansion

Add the following sentence to the system.web tag in Web. config:

Note: Do not expand too much, because if multiple people upload large files at the same time, it may cause server memory overflow, causing the server to crash.

Optimization 4: Exceeding the size of the upload request, preventing uploading and prompting the file to be too large
C # Side resolution:

if (Fileupload1.postedfile.contentlength> (1024x768*)) {Labei1.text="  file More than 10M, do not upload such a large! "; return ;}

C # End is bad, because if the file exceeds the maximum length, the C # end is limited, and the program crashes directly

JS End:

document.getElementById ("Button1"). onclick =function () {        //Remove the upload element        varFI1 = document.getElementById ("FileUpload1"); //determine if there is a selected file        if(fi1.value.length <= 0) {alert (' Please select the file you want to upload! ‘); return false; }        Else {            //Verify that the selected file length meets the criteria            if(Fi1.files[0].size > (1024 * 1024 * 10) {alert (' File too large, not allowed to upload! ‘); return false; }        }    };

Optimization 5: Limit the types of files that can be selected

In the FileUpload property, add accept= ". Jpg,.jpeg,.png"

Breakpoint Continuation:

1 usingSystem;2 usingSystem.Data;3 usingSystem.Configuration;4 usingSystem.Collections;5 usingsystem.web;6 usingSystem.Web.Security;7 usingSystem.Web.UI;8 usingSystem.Web.UI.WebControls;9 usingSystem.Web.UI.WebControls.WebParts;Ten usingSystem.Web.UI.HtmlControls; One usingSystem.IO; A  Public Partial classDFile:System.Web.UI.Page - {  - protected voidPage_Load (Objectsender, EventArgs e) the {  - }  - protected voidLinbtndfile_click (Objectsender, EventArgs e) - {  + //create a bit array - byte[] buffer =Newbyte[10240];  + //specifies the path to the file to download. A stringFilePath =@"d:\ Love-wise nook. rar";  at //or take the file name including the extension - stringFileName =Path.getfilename (filePath); -Stream FileStream =NULL;  - Try  - {  - //Open File inFileStream =NewFileStream (FilePath, FileMode.Open, FileAccess.Read, fileshare.read); - response.clear (); to //get the size of a file + LongFileSize =filestream.length; - Longsum =0;  the if(request.headers["Range"] !=NULL)  * {  $Response.statuscode =206;//An integer that represents the HTTP output status returned to the client. The default value is 200. Panax Notoginsengsum =Long. Parse (request.headers["Range"]. Replace ("bytes=",""). Replace ("-",""));  - }  the if(Sum! =0)  + {  AResponse.AddHeader ("Content-range","bytes"+ Sum. ToString () +"-"+ ((Long) (FileSize)). ToString () +"/"+filesize.tostring ());  the }  + //Get partial HTTP header information -Response.AddHeader ("Content-length", ((Long) (FileSize-sum)). ToString ());  $Response.ContentType ="Application/octet-stream";  $ //Get File Source -Response.AddHeader ("content-disposition","attachment; Filename="+Httputility.urlencode (Request.ContentEncoding.GetBytes (fileName));  - //Response.Flush (); thefilestream.position = sum;//set Current stream position -FileSize = FileSize-sum;Wuyi //when the file size is greater than 0, it enters the loop the  while(FileSize >0)  - {  Wu //determine if the client is still connected to the server - if(response.isclientconnected) About {  $ //gets the total number of bytes in the buffer. - intLength = filestream.read (buffer,0,10240);  - //Write Data -Response.OutputStream.Write (Buffer,0, length);  A //send the output of the buffer to the client + Response.Flush (); theBuffer =Newbyte[10240];  -FileSize = FileSize-length; $ }  the Else  the {  the //exit loop when user disconnects theFileSize =-1;  - }  in }  the }  the Catch(Exception ex) About {  theResponse.Write ("Error:"+Ex. Message);  the }  the finally  + {  - if(FileStream! =NULL)  the { Bayi //Close File the filestream.close (); the }  - Response.End (); - }  the }  the}

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Webform (File upload)