Attachments control

The Attachments control allows users to attach files to the SharePoint list item that the form is currently adding or editing. For list forms it is the list item of the form. For task forms it will be the attachments for the task list item, not the list item the workflow is running on.

Note: If the browser being used does not support browsing the file system and selecting attachments, the Browse button will be disabled.

This control is supported in Nintex Mobile, except for noted fields.

Control settings  

Following are the fields and options visible in the control settings dialog box for this form control.

Note: Several settings allow selection of Yes, No, or Expression. Selecting Expression allows you to construct a formula from reference tokens and functions. The expression must resolve to a Yes/No value at runtime to be valid. If the expression does not resolve to a Yes/No value, it will revert to the default.

Note: For information about the control properties tab in the Nintex Forms ribbon, see Control properties tab.

Section Field Description Nintex Mobile



The name of the control. The name is used for comparison validation and other control references.




(Responsive Forms Designer only)

Title of the control. The title is displayed as the label for the control.




(Responsive Forms Designer only)

Description of the control. The description displays additional information or instructions for the control.



Default control

When more than one attachment control is on the form, you must assign one of them as the default. If a default is not chosen, you will not be able to publish the form. The attachment control selected as the default will display any "orphaned" attachments on an item. An "orphaned" attachment is an attachment that was attached with no specific Nintex Forms attachment control associated with it. This can happen with items that are added either:

  • using forms that were published with previous versions of Nintex Forms or
  • other forms such as SharePoint forms.

Note: For Attachments controls used within Repeating Section controls, the Default control setting is automatically set to No and hidden. An attachment added to a list item using a Repeating Section control becomes orphaned if the form is republished without the corresponding Attachments control or Repeating Section control; any attachments orphaned in this way become visible when a default attachment control (Default control setting enabled) exists in the form.




Hide or show the control at runtime.


Formatting(Classic Forms Designer only)


CSS class

The CSS class to apply to the control. This is used to apply advanced styling options. The Custom CSS class is defined in Form Settings (refer to Form and Layout settings).




​Draws a line along the select border of the control.



Border Style

The style of the border.



Border Width (Pixels)

​The width of the border in pixels.



Border Color

The color of the border. This can either be a HEX code or a named color that is supported by html.



Padding Width (Pixels)

The amount of padding in pixels that will appear between the top, left and right border and the inner control.



Minimum attachments

​The number of attachments required for form submission.

Note: When a value is specified for this field, a red asterisk appears in the published form, to the right of the label associated with this control.



Minimum attachments error message

​The text of the error message displayed if form is submitted without the required number of attachments.

Example: "Résumé file must be attached."

Nintex Mobile displays the following error message by default for this validation item.

“You have not met the minimum number of required files.”



Maximum attachments setting

The setting to use for maximum attachments allowed:

  • Unlimited: The number of attachments is not validated.
  • Custom: The number of attachments is validated according to the value specified for Maximum attachments. When the maximum value is reached, the Add Attachment link is disabled.



Maximum attachments

​The highest number of attachments allowed for form submission.

Note: This field is displayed only when you select Custom for Maximum attachments setting.

Nintex Mobile displays the following error message by default for this validation item.

“You have exceeded the maximum allowed number of files.”



Allowed file formats (enter each format on its own line)

​The file extensions validated at the time of attachment. Enter each file extension (format) on its own line.





Note: Separate from the form-specific file formats specified here, the SharePoint server may block file formats (file types).

Nintex Mobile displays the following error message for any attached file type that is blocked by the SharePoint server.

“The selected file type is blocked by the server. Select a different file type.”



Disallowed file format error message

​The text of the error message displayed if an attempted file attachment fails validation according to Allowed file formats.

Nintex Mobile displays the following error message by default for this validation item.

​ “The selected file type is not allowed for this form. Select a different file type.”​


Related Topics

Forms designer
Control Settings
Controls In Use
List Item
List View
List Lookup
Shortcut keys
Inserting reference fields
Control Properties Ribbon