enhancement
major
minor
major
minor
A FileName constraint can be set on a tl:DataField, which may exclude certain files already on the client side.
In the case of a multi-upload, only the name of the first file is checked here.
All files to be uploaded should be checked here.
Improvement
The function `window.parent.services.form.DataItemControl.fileNameUpdate(ctrlID, iframeID, newValue) ` was called with `this.value ` as ` newValue `. However, the parameter contained only the first filename. Now, this.files is used instead, and the corresponding filenames are extracted from it, which are then used to call the FileNameUpdate command.
Test
For example, using a GalleryField of an A object in the demo. Upload multiple files at once (not via drag-and-drop; see #26740 for more on this) and select at least one file that does not match the allowed file types—for example, a text file. A corresponding error message should be displayed.