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Add Image Previews before Uploading Files in the Upload

Environment

Product Progress Kendo UI Upload for jQuery
Operating System Windows 10 64bit
Visual Studio version Visual Studio 2017
Preferred Language JavaScript

Description

How can I add an image preview before you upload a file when working with the Kendo UI Upload?

Solution

The following example demonstrates how to add an image preview and read the file in the select event of the Upload.

<div id="example">
    <h3>Add image preview before uploading file</h3>
        <input type="file" id="files">

    <script>
      $(document).ready(function() {
        $("#files").kendoUpload({
          async: {
            saveUrl: "save",
            removeUrl: "remove",
            autoUpload: false
          },
          multiple: false,
          select: function(e) {
            var fileInfo = e.files[0];
            var wrapper = this.wrapper;

            setTimeout(function(){
              addPreview(fileInfo, wrapper);
            });
          }
        });
      });

      function addPreview(file, wrapper) {
        var raw = file.rawFile;
        var reader  = new FileReader();

        if (raw) {
          reader.onloadend = function () {
            var preview = $("<img class='image-preview'>").attr("src", this.result);

            wrapper.find(".k-file[data-uid='" + file.uid + "'] .k-file-group-wrapper")
              .replaceWith(preview);
          };

          reader.readAsDataURL(raw);
        }
      }
    </script>
    <style>
      .image-preview {
        position: relative;
        vertical-align: top;
        height: 45px;
      }
    </style>
  </div>

See Also

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