Currently a full entry mask isn't supported, however you can use the ValidationAttribute Data Annotation
and set the PhoneNumberValidatorAttribute
You can submit a feedback request here
for the development team to consider adding a mask annotation as they work on the next release of the control. Requests and Bug reports submitted through the portal go directly into the team's backlog.
An alternative is to use the RadMaskedInput control
outside of the DataForm.
Lance | Tech Support Engineer, Sr.
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