Problem

InfoPath does not allow you to use character limits on multiline boxes. You can however, work around this issue by using a validation rule that prevents a user from submitting a form when it exceeds a specific number of characters.

Solution

• Open the form in InfoPath
• Select the field you wish to limit
• On the Ribbon, click on Home -> Manage Rules
• Add a New Validation Rule
• Call it whatever you like, e.g. “CheckStringLength”
• Set the condition as follows:

string-length(.)>250

where 250 is the character limit.

• The end result of your rule should look like this:

• Test your new validation rule by typing something that exceeds the number of characters you specified.
• A red box should appear around the field and you will not be able to submit the form until you correct it. It is advisable to include a tool tip to inform the user on the maximum number of characters.