This post is a contribution from Jaishree Thiyagrajan, an engineer with the SharePoint Developer Support team
When we add a files with name containing only symbols like "([{_$%]}).txt" as an attachment to a list, we will see the error "The file/folder name that contains characters that are not allowed" & the attachment will not be added. But the item will be added.
We need to create a ItemEventReceiver and use ItemAttachmentAdding method to achieve the required functionality
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public override void ItemAttachmentAdding(SPItemEventProperties properties) { base.ItemAttachmentAdding(properties); //write your logic to check for valid filename and cancel it out if you do not want to save the attachment. } |
We cannot use ItemAdding event for the above requirement as we would not able to get the attachment name because the ListItem is null.