how to remove a preview image only one before upload in asp.net c#

Question

This code is to preview image and I want to remove a preview image one of the many and remaining images still there before upload.

 <script src="//code.jquery.com/jquery-1.11.2.min.js" type="text/javascript"></script>
<script type="text/javascript">
    function ShowImagePreview(input) {
        if (input.files && input.files.length > 0) {
            for (var i = 0 ; i < input.files.length; i++) {
                var reader = new FileReader();
                reader.onload = function (e) {
                    $('#imgViewer').append($('<img>', { src: e.target.result, width: '50px', height: '50' }));

                };
                reader.readAsDataURL(input.files[i]);
            }
        }
        }
</script>

Answer 1

Instead of doing this using your code, there is an alternative for what you want. You just need to do it with the help of JQuery MultiFile , download it and reference on the page where you are going to upload files, you need to select one file at a time, before uploading you can browse multiple files and cancel whatever file you want. Complete code would be like this:

Reference of MultiSelect JQuery:

<script src="Scripts/jquery.MultiFile.js"></script>

.aspx code:

<asp:FileUpload ID="FileUpload1" runat="server" class="multi" />
<br />
<asp:Button ID="Upload" runat="server" Text="Upload Images"
        onclick="Upload_Click"/>

.cs code:

    protected void Upload_Click(object sender, EventArgs e)
    {
      HttpFileCollection hfc = Request.Files;
      for (int i = 0; i < hfc.Count; i++)
      {
        HttpPostedFile hpf = hfc[i];
        if (hpf.ContentLength > 0)
        {
          hpf.SaveAs(Server.MapPath("MyFiles") + "\\" +
          System.IO.Path.GetFileName(hpf.FileName));
          Response.Write("<b>File: </b>" + hpf.FileName + " <b>Size:</b> " +
                            hpf.ContentLength + " <b>Type:</b> " + hpf.ContentType + " Uploaded Successfully <br/>");
        }
     }
   }

It is a tested code, it works perfectly to address your problem.

Hope it helps!