upload-multiple-files-at-a-time.md

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title	How to upload multiple files at a time?
keywords	Dynamic Web TWAIN, Document Saving, upload files
breadcrumbText	How to upload multiple files at a time?
description	How to upload multiple files at a time?
date	2022-08-29 18:03:43 +0800
last_modified	2024-09-19 08:47:35 +0800

Document Saving

How to upload multiple files at a time?

Scenario:

After scanning multiple files, you might want to upload them one by one as individual images. Before version 13.1, you have to call the upload method(s) multiple times. From version 13.1+, you can do this in one go.

Solution:

You can use the methods ConvertToBlob and HTTPUpload to achieve this.

Steps:

1. In JS, write code similar to the following:

function UploadAsJPG() {
    var count = 0;
    DWTObject.ClearAllHTTPFormField();
    DWTObject.SetHTTPFormField("UploadedImagesCount",DWTObject.HowManyImagesInBuffer);

    function asyncFailureFunc(errorCode, errorString) {
        alert("ErrorCode: " + errorCode + "\r" + "ErrorString:" + errorString);
    };

    var onEmptyResponse = function () {
        console.log("Uploaded Successfully");
    };

    var onServerReturnedSomething = function (ecode,estring,resp) {
        console(resp);
    }

    var convertImage = function (_index) {
        DWTObject.ConvertToBlob(
            [_index], 
            Dynamsoft.DWT.EnumDWT_ImageType.IT_JPG,
            function (result) {
                DWTObject.SetHTTPFormField('image_' + _index, result, 'JPG_image_' + _index);
                count++;
                if (count < DWTObject.HowManyImagesInBuffer) {
                    convertImage(count);
                } else {
                    DWTObject.HTTPUpload("http://localhost:90/saveUploadedJPG.aspx", onEmptyResponse, onServerReturnedSomething);// Please replace the URL with yours.
                }
            }, 
            asyncFailureFunc
        );
    };

    convertImage(0);
}

2. On the server, add an action page to process the uploaded data, take c# as an example,

<%@ Page Language="C#" %>
<%
    try
    {
        String strImageName;
        String strInfo = HttpContext.Current.Request["UploadedImagesCount"];
        short uploadedImagesCount = Convert.ToInt16(strInfo);
        HttpFileCollection files = HttpContext.Current.Request.Files;
        for (short i = 0; i < uploadedImagesCount; i++)
        {
            HttpPostedFile uploadfile = files["image_" + i.ToString()];
            strImageName = uploadfile.FileName;
    
            uploadfile.SaveAs(Server.MapPath(".") + "\\UploadedImages\\" + strImageName + ".jpg");
        }
    }
    catch
    {
    }
%>