Duplicate File Detection

Demo uploads land in a temporary store and are swept after 60 minutes. To keep files, handle FileUploaded — see Single File for the complete save pattern.

Prevent users from uploading the same file twice using EnableDuplicateCheck="true". Use DuplicateHashAlgorithm to specify the hashing method for content-based detection.

What you should see: add the same file twice and the second is refused - detection is by SHA-256 content hash, so a renamed copy is still caught.

Drag & drop files here, or paste from clipboard

<au:AjaxFileUpload ID="Uploader1" runat="server"
 AllowMultiple="true"
 EnableDuplicateCheck="true"
 DuplicateHashAlgorithm="sha256"
 ButtonText="Select Files"
 AutoUpload="true"
 ShowProgress="true" />

Try selecting the same file twice to see it detected as a duplicate.