how to check image name already exist in folder using Uploadify

Hi!

I did excactly this.

in my ASPx File JavaScript Code I use

$("#UPLOAD_BUTTON").uploadify({
                  'buttonClass'   : "ui-icon ui-icon-plus",
                  'swf'            : '/web/uploader/uploadify.swf',                  
                  'uploader'       : '/web/uploader/Uploadify.ashx?ASPSESSID=<% =Session.SessionID %>',
                  'cancelImage'    : '/web/uploader/uploadify-cancel.png',
                  'folder'         : '/uploads',
                  'multi'          : true,
                  'auto'           : true,
                  'checkExisting'  : '/web/uploader/Uploadify.ashx?check=true',
                  'queueID'        : "UploadFilesQueue",
                  'buttonText'     : ' ',          
                  'hideButton'     : true,  
                  'fileTypeExts'   : '*.*',
                  'fileTypeDesc'   : 'Alle Dateien',
                  'onQueueComplete': function(event,data) {                      
                  },
                  postData : {
                    "stepID" : $("#lblStepID").text(),
                    "ASPSESSID" : "<% =Session.SessionID %>",                    
                  }
              });

you need to pass the SessionID as a parameter and grab it in the Global.asax File or you will create a new ASP.NET session on every Upload.

In the jquery.uploadify.js File you need to find this function and modify it

function onUploadStart(file)

There you can react on the Returncode from you Upload-ASHX file.

I use different return codes for different conditions like
ReturnCode=1 -> File allready Exists
ReturnCode=2 -> File is to Big
....

this is the (a bit modified) content of my upload.ashx file

<![CDATA[<%@ WebHandler Language="C#" Class="esp.Web.Upload" %>]]>

using System;
using System.Web;
using System.IO;
using System.Web.Util;
using System.Web.SessionState;
using System.Web.Configuration;

using System.Collections.Generic;

using esp.Web.uploader;
using log4net;

namespace esp.Web {
    public class Upload : IHttpHandler, IRequiresSessionState {

        public void ProcessRequest(HttpContext context) {
            context.Response.ContentType = "text/plain";
            context.Response.Expires = -1;
            var  log = LogManager.GetLogger(typeof(Upload));
            log.Debug("Upload: ProcessRequest");
            try {                                
                var usr = ValidateSession(context, log);
                if( usr != null ) {
                    if( context.Request.Params["check"] != null ) {
                        String filename = context.Request.Params["filename"];
                        TestForUpload(context, log, usr, filename);
                    } else {
                        UploadFile(context, log, usr);
                    }
                } else {
                    context.Response.Write("Error: I'm a Teapot!");
                    context.Response.StatusCode = 418;
                }
            } catch( Exception ex ) {
                log.Error(ex.ToString( ));
                context.Response.Write("Error: " + ex.Message);
                context.Response.StatusCode = 500;
            }
        }

        protected void TestForUpload(HttpContext context, ILog log, <myuserclass> usr, String filename) {
            IUploadFileDispatch disp = (IUploadFileDispatch)context.Session["FILE_DISPATCH"];
            HttpRuntimeSection section = System.Configuration.ConfigurationManager.GetSection("system.web/httpRuntime") as HttpRuntimeSection;
            long fileSize = Int64.Parse(context.Request.Params["filesize"]);
            if( fileSize > section.MaxRequestLength ) {
                context.Response.Write("2");
                context.Response.StatusCode = 200;
            } else {
                if( disp.ValidateFile("", filename) ) {
                    context.Response.Write("0");
                    context.Response.StatusCode = 200;
                } else {
                    context.Response.Write("1");
                    context.Response.StatusCode = 200;
                }
            }
        }

        protected void UploadFile(HttpContext context, ILog log) {
                       
        }

        public bool IsReusable {
            get {
                return false;
            }
        }

        public <myuserclass> ValidateSession(HttpContext context, ILog  log) {            
            
        }

    }
}
</myuserclass></myuserclass>