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Hi Afroz,
RadAsyncUpload does not provide a built-in way to detect or block files that are dragged and dropped from inside a compressed ZIP folder. When a user drags a file out of a ZIP archive and drops it onto the upload area, the browser treats it as a regular file, so there is no metadata or property available to determine its origin.
Current Options and Limitations:
Blocking ZIP Files:
You can block users from uploading ZIP files themselves by validating file extensions (e.g., ".zip"). However, this does not prevent users from extracting files from a ZIP and then uploading them.Detecting ZIP-Origin Files:
There is no browser API or client-side JavaScript method to determine if a dropped file was originally inside a ZIP archive. All files, regardless of their source, are seen as regular files by the upload control.Client-Side Validation:
You can use the OnClientFileDropped event to inspect file properties (such as name or type) and implement custom rules, but you cannot detect ZIP-origin files this way.
Alternative Approaches:
Server-Side Validation:
If there are specific file types or content you want to block, consider adding server-side validation after upload to inspect file signatures or contents.Disabling Drag and Drop:
If drag and drop is not required, you can disable this functionality in RadAsyncUpload to force users to use the file picker dialog, which might help control the user experience:
Related Feedback:
- There is a declined feature request to block folder uploads via drag and drop in RadAsyncUpload, which is somewhat related:
Summary:
- It is not technically possible to prevent users from dragging and dropping files that were extracted from a ZIP folder, as browsers do not expose this information.
- You can block ZIP files by extension or disable drag-and-drop if that helps your scenario.
Regards,
Rumen
Progress Telerik