Image preview with Fileupload asp.net mvc and JQuery

I am trying to view an image that a user is trying to upload. This is the code I am using. This works well in all major browsers, but I'm wondering if there is a better way to achieve this without using a session (although I'm clearing the session)? I don't want to use Flash.

   @using (Html.BeginForm("UploadImage", "Home", FormMethod.Post, new { id = "fileuploadform", @enctype = "multipart/form-data" }))
    {
        <input id="fileupload" type="file" onchange="ChangeImage()" name="files" multiple>
        <div id="preview">
            <img src="#" id="imgThumbnail" alt="preview" />
        </div>

    }
            <script>
            $(function ChangeImage() {
                $('#fileuploadform').fileupload({
                    done: function (e, data) {
                        var d = new Date();
                        $('#imgThumbnail')[0].src = "/Home/ImageLoad?a=" + d.getTime();
                    }
                });
            });
        </script>

[HttpPost]
public ActionResult UploadImage(IEnumerable<HttpPostedFileBase> files, PostViewModel model)
{

    Session["ContentLength"] = Request.Files[0].ContentLength;
    Session["ContentType"] = Request.Files[0].ContentType;
    byte[] b = new byte[Request.Files[0].ContentLength];
    Request.Files[0].InputStream.Read(b, 0, Request.Files[0].ContentLength);
    Session["ContentStream"] = b;
    return Content(Request.Files[0].ContentType + ";" + Request.Files[0].ContentLength);
}

   public ActionResult ImageLoad(int? id)
    {
        byte[] b = (byte[])Session["ContentStream"];
        int length = (int)Session["ContentLength"];
        string type = (string)Session["ContentType"];
        Session["ContentLength"] = null;
        Session["ContentType"] = null;
        Session["ContentStream"] = null;
        return File(b, type);
    }

      

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3 answers


Have you tried this solution?

Previewing an image before uploading it



This solution is purely client-side and doesn't need to be uploaded to the server before being viewed. :)

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You can improve the action code like this:



HttpPostedFileBase picFile = Request.Files["fileUpload"];
if (picFile != null && picFile.ContentLength > 0)
{
     byte[] pic = new byte[picFile.ContentLength];
     picFile.InputStream.Read(pic, 0, picFile.ContentLength);
     // you can use pic ....
}

      

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  Image preview with Fileupload Asp.Net C # MVC with Razor Framework and jQuery?

This will allow multiple files to be viewed simultaneously as thumbnails.

On View Asp.Net C # MVC with Razor Framework

<div class="form-group">
   @Html.LabelFor(model => model.ImageMedias)
   <div class="input-group">
      <div class="custom-file">
         @Html.TextBoxFor(model => model.ImageMedias, "", new { @class = "custom-file-input", @type = "file", @multiple = "multiple", @accept = ".jfif,.jpg,.jpeg,.png,.gif" })
         <label class="custom-file-label" for="InputFile">Choose file</label>
      </div>
   </div>
   @Html.ValidationMessageFor(model => model.ImageMedias)   
   <div id="divImageMediaPreview">
   </div>
</div>

      

Script

Script
$("#ImageMedias").change(function () {
    if (typeof (FileReader) != "undefined") {
        var dvPreview = $("#divImageMediaPreview");
        dvPreview.html("");            
        $($(this)[0].files).each(function () {
            var file = $(this);                
                var reader = new FileReader();
                reader.onload = function (e) {
                    var img = $("<img />");
                    img.attr("style", "width: 150px; height:100px; padding: 10px");
                    img.attr("src", e.target.result);
                    dvPreview.append(img);
                }
                reader.readAsDataURL(file[0]);                
        });
    } else {
        alert("This browser does not support HTML5 FileReader.");
    }
});

      

I hope this helps.

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