javascript - How to copy from value file input to dynamic input file value in java scripts?

Question

I have a input file multiple choose file, when choosing files in input file multiple divide to the dynamic input file and submit a form to server.

1. Use Asp.net MVC
2. Get all file in server by using HttpPostedFileBase f = form[key];
3. use js and jQuery

HTML

Out Side Form

<input type="file" name="files" id="files" onchange="readFile(this)" multiple accept="image/png, image/jpeg, image/jpg," capture class="file" style="display:none" value="" />

In side form

@using (Html.BeginForm("EditImage", "Client", FormMethod.Post, new { enctype = "multipart/form-data" }))
{
    <input type="hidden" id="id_client" name="id_client" value="@ViewBag.Client" />
    <div class="row">
        <div class="col-md-12">
            <div class="dropzone dz-clickable" onclick="document.getElementById('files').click()" id="imgZone">
                <div class="dz-default dz-message"><span>Click Here to choose file</span></div>
            </div>
        </div>
        <div class="col-md-12">
            <br />
            <div class="row">
                <div class="col-md-6"><p class="btn btn-danger btn-lg disabled btn-block" id="delete" onclick="Clear()">Clear</p></div>
                <div class="col-md-6"><input type="button" onclick="Send(this)" name="add" id="add" class="btn btn-success btn-lg disabled btn-block" value="Submit" /></div>
            </div>
        </div>
    </div>
}

jQuery Code for set value, create and preview image

function readFile(input) {
    //CheckFileUpload(input.files.length)
    if (input.files && input.files[0]) {
        var img, inputID = 0;
        for (var i = 0; i < input.files.length; i++) {
            var reader = new FileReader();
            reader.onload = (function (f) {
                return function (e) {
                    console.table(f);
                    img = '<div class="dz-preview dz-processing dz-error dz-complete dz-image-preview">';
                    img += '    <input type="file" id="file_' + inputID + '" name="file_' + inputID + '" class="d-none" value="' + f + '" style="display:none" />';
                    img += '    <div class="dz-image shadow"><img data-dz-thumbnail="" class="w-100 h-100" alt="banner.jpg" src="' + e.target.result + '"></div>';
                    img += '    <div class="dz-details">';
                    img += '        <div class="dz-size"><span data-dz-size="">' + formatBytes(f.size) + '</span></div>';
                    img += '        <div class="dz-filename"><span data-dz-name="">' + f.type + '</span></div>';
                    img += '        <div class="mt-1 btn btn-danger btn-delete"><i class="fas fa-trash"></i></div>';
                    img += '    </div>';
                    img += '</div>';
                    $('#imgZone').append(img);
                    inputID++;
                }

            })(input.files[i]);
            reader.readAsDataURL(input.files[i]);
        }
    }
}

C# Code { In Server site (Server Code for get files) }

public ActionResult EditImage(long? id_client)
{
    //For testing
    //var filesRequest = Request.Files;
    //HttpPostedFileBase file = filesRequest["file_1"];

    var files = new HttpPostedFile[Request.Files.Count];
    Request.Files.CopyTo(files, 0);
    if (files == null)
        return RedirectToAction("Detail", new { id = id_client });
    if (files[0] != null)
        FileUpload(id_client, "~\Documents\Client\boards", files);
    return RedirectToAction("ViewImage", new { id = id_client, camBack = false });
}

when submit form files not null but fileName is empty

File output Why File name is empty ?

Files output When submited form all input POST but Content Length equals 0 and FileName is Empty

**Summary My Quotation **

1. How to files in server site by my way ( my code ) ?
2. I don't know problem in server site or client site !!!
3. no problem if any way and all change code for new way

Answer 1

i try to find new way

Hold on hidden input Base 64 image stream then pass to server in server convert to Image type

jQuery and JS

function readFile(input) {
    CheckFileUpload(input.files.length)
    if (input.files && input.files[0]) {
        var img, inputID = 0;
        for (var i = 0; i < input.files.length; i++) {
            var reader = new FileReader();
            reader.onload = (function (f) {
                return function (e) {
                    //<input type="file" id="file_' + inputID + '" name="file_' + inputID + '" class="d-none" value="' + f + '" style="display:none" />';
                    var fileInput = $('<input/>')
                        .attr('type', "hidden")
                        .attr('name', 'file_' + inputID + '')
                        .attr('id', 'file_' + inputID + '')
                        .attr('value', e.target.result);
                    $('#imgZone').append(fileInput);
                    inputID++;
                }

            })(input.files[i]);
            reader.readAsDataURL(input.files[i]);
        }
    }

C#

var filesRequest = Request.Form;
    string file = filesRequest["file_1"];
    byte[] bytes = Convert.FromBase64String(file); // Replace file here
    System.Drawing.Image image;
    using (MemoryStream ms = new MemoryStream(bytes))
    {
        image = System.Drawing.Image.FromStream(ms);
    }

Problem in code: Must base 64 string substring or replace data:image/jpeg;base64,