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File Uploader - Custom Drop Zone

The FileUploader component supports the drag-and-drop functionality to upload files.

In this demo, the dropZone property specifies the HTML element in which you can drag and drop files for upload. The dropZoneEnter and dropZoneLeave events allow you to customize the drop zone when the mouse pointer enters and leaves this zone while dragging the file.

Backend API
<div class="widget-container flex-box"> <span>Profile Picture</span> <div id="dropzone-external" class="flex-box"> <img id="dropzone-image" src="#" hidden alt="" onload="toggleImageVisible(true)" /> <div id="dropzone-text" class="flex-box"> <span>Drag & Drop the desired file</span> <span>…or click to browse for a file instead.</span> </div> @(Html.DevExtreme().ProgressBar() .ID("upload-progress") .Min(0) .Max(100) .Width("30%") .ShowStatus(false) .Visible(false) ) </div> @(Html.DevExtreme().FileUploader() .DialogTrigger("#dropzone-external") .DropZone("#dropzone-external") .ID("file-uploader") .Name("myFile") .Multiple(false) .AllowedFileExtensions(new[] { ".jpg", ".jpeg", ".gif", ".png" }) .UploadMode(FileUploadMode.Instantly) .UploadUrl(Url.Action("Upload", "FileUploader")) .Visible(false) .OnDropZoneEnter("fileUploader_dropZoneEnter") .OnDropZoneLeave("fileUploader_dropZoneLeave") .OnUploaded("fileUploader_uploaded") .OnProgress("fileUploader_progress") .OnUploadStarted("fileUploader_uploadStarted") ) </div> <script> function getProgressBarInstance() { return $("#upload-progress").dxProgressBar("instance"); } function fileUploader_dropZoneEnter({ component, dropZoneElement, event }) { if(dropZoneElement.id === "dropzone-external") { const items = event.originalEvent.dataTransfer.items; const allowedFileExtensions = component.option('allowedFileExtensions'); const draggedFileExtension = `.${items[0].type.replace(/^image\//, '')}`; const isSingleFileDragged = items.length === 1; const isValidFileExtension = allowedFileExtensions.includes(draggedFileExtension); if (isSingleFileDragged && isValidFileExtension) { toggleDropZoneActive(dropZoneElement, true); } } } function fileUploader_dropZoneLeave(e) { if(e.dropZoneElement.id === "dropzone-external") toggleDropZoneActive(e.dropZoneElement, false); } function fileUploader_uploaded(e) { const file = e.file; const fileReader = new FileReader(); fileReader.onload = function() { toggleDropZoneActive($("#dropzone-external")[0], false); $("#dropzone-image")[0].src = fileReader.result; } fileReader.readAsDataURL(file); $("#dropzone-text")[0].style.display = "none"; getProgressBarInstance().option({ visible: false, value: 0 }); } function fileUploader_progress(e) { getProgressBarInstance().option("value", e.bytesLoaded / e.bytesTotal * 100); } function fileUploader_uploadStarted() { toggleImageVisible(false); getProgressBarInstance().option("visible", true); } function toggleDropZoneActive(dropZone, isActive) { dropZone.classList.toggle('dropzone-active', isActive); } function toggleImageVisible(visible) { $("#dropzone-image")[0].hidden = !visible; } </script>
using DevExtreme.NETCore.Demos.Models.FileUploader; using Microsoft.AspNetCore.Cors; using Microsoft.AspNetCore.Http; using Microsoft.AspNetCore.Mvc; using System; using System.IO; using System.Linq; using System.Text.Json; namespace DevExtreme.NETCore.Demos.Controllers { public partial class FileUploaderController : Controller { public ActionResult CustomDropzone() { return View(); } } }
#dropzone-external { width: 350px; height: 350px; background-color: rgb(183 183 183 / 10%); border-width: 2px; border-style: dashed; padding: 10px; border-color: var(--dx-color-border); } #dropzone-external > * { pointer-events: none; } #dropzone-external.dropzone-active { border-style: solid; border-color: var(--dx-color-primary); } .widget-container > span { font-size: 22px; font-weight: bold; margin-bottom: 16px; } #dropzone-image { max-width: 100%; max-height: 100%; } #dropzone-text > span { font-weight: 100; opacity: 0.5; } #upload-progress { display: flex; margin-top: 10px; } .flex-box { display: flex; flex-direction: column; justify-content: center; align-items: center; }
NOTE

Allowed file extensions: .jpg, .jpeg, .gif, .png

Maximum file size: 4 MB