Minimum File Size

Enforce a minimum file size using MinFileSize to reject files that are too small (e.g., empty or placeholder files).

Min 10 KB

Drag & drop files here, or paste from clipboard

<au:AjaxFileUpload ID="Uploader1" runat="server"
    MinFileSize="10KB"
    ButtonText="Select File (min 10KB)"
    AutoUpload="true"
    ShowProgress="true" />

Try selecting a very small file (under 10 KB) to see the validation error.