Avoiding Multiple File Selection

[Alp]

Hi,

I am trying to avoid same file being selected more than one time. I have seen posts and replies such as
http://www.telerik.com/community/forums/aspnet-ajax/async-upload/avoid-duplicate-in-asyncupload-multiple-drag-and-drop.aspx
but when multiple file is selected (not drag/drop but selection from file dialog) all those functions are failing. Mostly, they miss the duplicate item at index 0. I have tried many other ways but could not figure out a solid and reliable way to achieve this.

Please note that I am also handling the file removed event and do some external stuff there, and I either need to find a way for one the scenarios below: 

* catch and cancel duplicates when file is selected (before uploading etc.), in which case I do not need the file removed handler (since file was not actually selected, it was cancelled) 

or

* catch duplicates at files uploaded event, and remove them from file list, properly calling file removed event

When single file is selected, previously suggested functions work fine, but when 6-8 files selected, problems show up.

Please advise.

Thanks.

[Hristo Valyavicharski]

Hi Alp,

I would suggest you to perform file duplication check in OnClientFileUploading event:

function OnClientFileUploading(sender, args) {
    var fileName = args.get_fileName();

    for (var i = 0; i < sender.getUploadedFiles().length; i++) {
        if (sender.getUploadedFiles()[i] === fileName) {
            console.log('duplicated' + fileName);
            args.set_cancel(true);
            sender.deleteFileInputAt(sender.getUploadedFiles().length);
            $(".ErrorHolder").append(fileName + "duplicate file name have been remove automatically.<br/>").fadeIn("slow");
        }

    }
}

    <telerik:RadAsyncUpload
        ID="RadAsyncUpload1"
        OnClientFileUploading="OnClientFileUploading"
        MultipleFileSelection="Automatic"
        TargetFolder="~/Uploads"
        runat="server">
    </telerik:RadAsyncUpload>
<div class="ErrorHolder" style="background-color:red"></div>

This validation should be working with both Single and Multiple files selection.

Regards,
Hristo Valyavicharski
Telerik