PDFTron WebViewer

Class: Field

Core.PDFNet. Field

new Field( [leaf_node] [, builder])

An interactive form (sometimes referred to as an AcroForm) is a collection of fields for gathering information interactively from the user. A PDF document may contain any number of Fields appearing on any combination of pages, all of which make up a single, global interactive form spanning the entire document. PDFNet fully supports reading, writing, and editing PDF forms and provides many utility methods so that work with forms is simple and efficient. Using PDFNet forms API arbitrary subsets of form fields can be imported or exported from the document, new forms can be created from scratch, and the appearance of existing forms can be modified. In PDFNet Fields are accessed through FieldIterator-s. The list of all Fields present in the document can be traversed as follows: 
FieldIterator itr = pdfdoc.GetFieldIterator();
for(; itr.HasNext(); itr.Next()) {
  Field field = itr.Current();
  Console.WriteLine("Field name: {0}", field.GetName());
 }
For a full sample, please refer to 'InteractiveForms' sample project. To search field by name use FieldFind method. For example: 
FieldIterator itr = pdfdoc.FieldFind("name");
if (itr.HasNext()) {
  Console.WriteLine("Field name: {0}", itr.Current().GetName());
}
else { ...field was not found... }
If a given field name was not found or if the end of the field list was reached the iterator HasNext() will return false. If you have a valid iterator you can access the Field using Current() method. For example: Field field = itr.Current(); Using Flatten(...) method it is possible to merge field appearances with the page content. Form 'flattening' refers to the operation that changes active form fields into a static area that is part of the PDF document, just like the other text and images in the document. A completely flattened PDF form does not have any widget annotations or interactive fields.
Parameters:
Name Type Argument Description
leaf_node Core.PDFNet.Obj <optional>
builder Core.PDFNet.ElementBuilder <optional>
Properties:
Name Type Description
leaf_node Core.PDFNet.Obj
builder Core.PDFNet.ElementBuilder

Members

<static> EventType

Type:
  • number
Properties:
Name Type Description
e_action_trigger_keystroke number
e_action_trigger_format number
e_action_trigger_validate number
e_action_trigger_calculate number

<static> Flag

Type:
  • number
Properties:
Name Type Description
e_read_only number
e_required number
e_no_export number
e_pushbutton_flag number
e_radio_flag number
e_toggle_to_off number
e_radios_in_unison number
e_multiline number
e_password number
e_file_select number
e_no_spellcheck number
e_no_scroll number
e_comb number
e_rich_text number
e_combo number
e_edit number
e_sort number
e_multiselect number
e_commit_on_sel_change number

<static> TextJustification

Type:
  • number
Properties:
Name Type Description
e_left_justified number
e_centered number
e_right_justified number

<static> Type

Type:
  • number
Properties:
Name Type Description
e_button number
e_check number
e_radio number
e_text number
e_choice number
e_signature number
e_null number

Methods

<static> create(field_dict)

construct a PDF::Field from a SDF dictionary representing a terminal field node.
Parameters:
Name Type Description
field_dict Core.PDFNet.Obj the SDF dictionary to construct the field from.
Returns:
A promise that resolves to an object of type: "PDFNet.Field"
Type
Promise.<Core.PDFNet.Field>

eraseAppearance()

removes any appearances associated with the field.
Returns:
Type
Promise.<void>

findInheritedAttribute(attrib)

Some of the Field attributes are designated as inheritable. If such an attribute is omitted from a Field object, its value is inherited from an ancestor node in the Field tree. If the attribute is a required one, a value must be supplied in an ancestor node; if it is optional and no inherited value is specified, the default value should be used. The function walks up the Field inheritance tree in search for specified attribute.
Parameters:
Name Type Description
attrib string
Returns:
A promise that resolves to the attribute value if the given attribute name was found or a NULL object if the given attribute name was not found. Resources dictionary (Required; inheritable) MediaBox rectangle (Required; inheritable) CropBox rectangle (Optional; inheritable) Rotate integer (Optional; inheritable)
Type
Promise.<Core.PDFNet.Obj>

flatten(page)

Flatten/Merge existing form field appearances with the page content and remove widget annotation. Form 'flattening' refers to the operation that changes active form fields into a static area that is part of the PDF document, just like the other text and images in the document. A completely flattened PDF form does not have any widget annotations or interactive fields.
Parameters:
Name Type Description
page Core.PDFNet.Page page object to flatten Note: an alternative approach to set the field as read only is using Field.SetFlag(Field::e_read_only, true) method. Unlike Field.SetFlag(...), the result of Flatten() operation can not be programatically reversed.
Returns:
Type
Promise.<void>

getDefaultAppearance()

Returns:
A promise that resolves to the default graphics state that should be used in formatting the text. The state corresponds to /DA entry in the field dictionary.
Type
Promise.<Core.PDFNet.GState>

getDefaultValue()

Returns:
A promise that resolves to the default value to which the field reverts when a reset-form action is executed or NULL if the default value is not specified. The format of field's value varies depending on the field type.
Type
Promise.<Core.PDFNet.Obj>

getDefaultValueAsString()

Returns:
A promise that resolves to a string of the default value to which the field reverts when a reset-form action is executed or NULL if the default value is not specified. The format of field's value varies depending on the field type.
Type
Promise.<string>

getFlag(flag)

Parameters:
Name Type Description
flag number 
PDFNet.Field.Flag = {
	e_read_only : 0
	e_required : 1
	e_no_export : 2
	e_pushbutton_flag : 3
	e_radio_flag : 4
	e_toggle_to_off : 5
	e_radios_in_unison : 6
	e_multiline : 7
	e_password : 8
	e_file_select : 9
	e_no_spellcheck : 10
	e_no_scroll : 11
	e_comb : 12
	e_rich_text : 13
	e_combo : 14
	e_edit : 15
	e_sort : 16
	e_multiselect : 17
	e_commit_on_sel_change : 18
}
Returns:
A promise that resolves to the value of given field flag
Type
Promise.<boolean>

getJustification()

Returns:
A promise that resolves to the form of quadding (justification) to be used in displaying the text fields.
Type
Promise.<number>
Example
Return value enum:
<pre>
PDFNet.Field.TextJustification = {
	e_left_justified : 0
	e_centered : 1
	e_right_justified : 2
}
</pre>

getMaxLen()

Returns:
A promise that resolves to the maximum length of the field's text, in characters, or a negative number if the length is not limited. Note: This method is specific to a text field.
Type
Promise.<number>

getName()

Returns:
A promise that resolves to a string representing the fully qualified name of the field (e.g. "employee.name.first").
Type
Promise.<string>

getOpt(index)

Parameters:
Name Type Description
index number index position of the option to retrieve.
Returns:
A promise that resolves to the string of the option at the givent index. Note: The index must be less than the value returned by GetOptCount().
Type
Promise.<string>

getOptCount()

Returns the total number of options in a list or combo box.
Returns:
A promise that resolves to an object of type: "number"
Type
Promise.<number>

getPartialName()

Returns:
A promise that resolves to a string representing the partial name of the field (e.g. "first" when "employee.name.first" is fully qualified name).
Type
Promise.<string>

getSDFObj()

Returns:
A promise that resolves to the underlying SDF/Cos object.
Type
Promise.<Core.PDFNet.Obj>

getTriggerAction(trigger)

Get the Action associated with the selected Field Trigger event.
Parameters:
Name Type Description
trigger number 
PDFNet.Field.EventType = {
	e_action_trigger_keystroke : 13
	e_action_trigger_format : 14
	e_action_trigger_validate : 15
	e_action_trigger_calculate : 16
}
the type of trigger event to get
Returns:
A promise that resolves to the Action Obj if present, otherwise NULL
Type
Promise.<Core.PDFNet.Obj>

getType()

Returns:
A promise that resolves to the field's value, whose type/format varies depending on the field type. See the descriptions of individual field types for further information.
Type
Promise.<number>
Example
Return value enum:
<pre>
PDFNet.Field.Type = {
	e_button : 0
	e_check : 1
	e_radio : 2
	e_text : 3
	e_choice : 4
	e_signature : 5
	e_null : 6
}
</pre>

getUpdateRect()

Returns:
A promise that resolves to the rectangle that should be refreshed after changing a field.
Type
Promise.<Core.PDFNet.Rect>

getValue()

Returns:
A promise that resolves to the value of the Field (the value of its /V key) or NULL if the value is not specified. The format of field's value varies depending on the field type.
Type
Promise.<Core.PDFNet.Obj>

getValueAsBool()

Returns:
A promise that resolves to field value as a boolean. Note: This method is usually for check-box and radio button fields.
Type
Promise.<boolean>

getValueAsString()

Returns:
A promise that resolves to a string of the value of the Field (the value of its /V key) or NULL if the value is not specified. The format of field's value varies depending on the field type.
Type
Promise.<string>

isAnnot()

Returns:
A promise that resolves to true if this Field is a Widget Annotation Determines whether or not this Field is an Annotation.
Type
Promise.<boolean>

isLockedByDigitalSignature()

Returns whether modifying this field would invalidate a digital signature in the document.
Returns:
A promise that resolves to whether modifying this field would invalidate a digital signature in the document
Type
Promise.<boolean>

isValid()

Returns:
A promise that resolves to whether this is a valid (non-null) Field. If the function returns false the underlying SDF/Cos object is null and the Field object should be treated as null as well.
Type
Promise.<boolean>

refreshAppearance()

regenerates the appearance stream for the Widget Annotation containing variable text. Call this method if you modified field's value and would like to update field's appearance. Note: If this field contains text, and has been added to a rotated page, the text in the field may be rotated. If RefreshAppearance is called *after* the field is added to a rotated page, then any text will be rotated in the opposite direction of the page rotation. If this method is called *before* the field is added to any rotated page, then no counter rotation will be applied. If you wish to call RefreshAppearance on a field already added to a rotated page, but you don't want the text to be rotated, you can do one of the following; temporarily un-rotate the page, or, temporarily remove the "P" object from the field.
Returns:
Type
Promise.<void>

rename(field_name)

modifies the field name.
Parameters:
Name Type Description
field_name string a string representing the fully qualified name of the field (e.g. "employee.name.first").
Returns:
Type
Promise.<void>

setFlag(flag, value)

Flags specifying various characteristics of the fields. Field flags common to all field types: ---------------------------------------------- If e_read_only flag is set the user may not change the value of the field. Any associated widget annotations will not interact with the user; that is, they will not respond to mouse clicks or change their appearance in response to mouse motions. This flag is useful for fields whose values are computed or imported from a database. If e_required flag is set, the field must have a value at the time it is exported by a submit-form action. If e_no_export flag is set, the field must not be exported by a submit-form action. Field flags specific to radio buttons: ---------------------------------------------- If e_toggle_to_off is clear, exactly one radio button must be selected at all times; clicking the currently selected button has no effect. If set, clicking the selected button deselects it, leaving no button selected. If e_radios_in_unison is set, a group of radio buttons within a radio button field that use the same value for the on state will turn on and off in unison; that is if one is checked, they are all checked. If clear, the buttons are mutually exclusive (the same behavior as HTML radio buttons). Field flags specific to text fields: ---------------------------------------------- If e_multiline is set, the field can contain multiple lines of text; if clear, the field's text is restricted to a single line. If e_password If set, the field is intended for entering a secure password that should not be echoed visibly to the screen. Characters typed from the keyboard should instead be echoed in some unreadable form, such as asterisks or bullet characters. The value is not stored if this flag is set. If e_file_select is set, the text entered in the field represents the pathname of a file whose contents are to be submitted as the value of the field. If e_no_spellcheck is set, text entered in the field is not spell-checked. If e_no_scroll is set, the field does not scroll (horizontally for single-line fields, vertically for multiple-line fields) to accommodate more text than fits within its annotation rectangle. Once the field is full, no further text is accepted. If e_comb is set, the field is automatically divided into as many equally spaced positions, or combs, as the value of MaxLen, and the text is laid out into those combs. Meaningful only if the MaxLen entry is present in the text field and if the Multiline, Password, and FileSelect flags are clear. If e_rich_text is set, the value of this field should be represented as a rich text string. If the field has a value, the RV entry of the field dictionary specifies the rich text string. Field flags specific to choice fields: ---------------------------------------------- If e_combo is set, the field is a combo box; if clear, the field is a list box. If e_edit is set, the combo box includes an editable text box as well as a dropdown list; if clear, it includes only a drop-down list. This flag is meaningful only if the e_combo flag is set. If e_sort is set, the field's option items should be sorted alphabetically. This flag is intended for use by form authoring tools, not by PDF viewer applications. Viewers should simply display the options in the order in which they occur in the Opt array. If e_multiselect is set, more than one of the field's option items may be selected simultaneously; if clear, no more than one item at a time may be selected. If e_commit_on_sel_change is set, the new value is committed as soon as a selection is made with the pointing device. This option enables applications to perform an action once a selection is made, without requiring the user to exit the field. If clear, the new value is not committed until the user exits the field.
Parameters:
Name Type Description
flag number 
PDFNet.Field.Flag = {
	e_read_only : 0
	e_required : 1
	e_no_export : 2
	e_pushbutton_flag : 3
	e_radio_flag : 4
	e_toggle_to_off : 5
	e_radios_in_unison : 6
	e_multiline : 7
	e_password : 8
	e_file_select : 9
	e_no_spellcheck : 10
	e_no_scroll : 11
	e_comb : 12
	e_rich_text : 13
	e_combo : 14
	e_edit : 15
	e_sort : 16
	e_multiselect : 17
	e_commit_on_sel_change : 18
}
value boolean
Returns:
Type
Promise.<void>

setJustification(j)

sets the justification to be used in displaying the text field.
Parameters:
Name Type Description
j number 
PDFNet.Field.TextJustification = {
	e_left_justified : 0
	e_centered : 1
	e_right_justified : 2
}
enum representing justification to set the text field to, options are e_left_justified, e_centered and e_right_justified Note: This method is specific to a text field.
Returns:
Type
Promise.<void>

setMaxLen(max_len)

sets the maximum length of the field's text, in characters.
Parameters:
Name Type Description
max_len number maximum length of a field's text. Note: This method is specific to a text field.
Returns:
Type
Promise.<void>

setValue(value)

Sets the value of the field (i.e. the value of the field's /V key). The format of field's value varies depending on the field type.
Parameters:
Name Type Description
value Core.PDFNet.Obj the new field value. Note: in order to remove/erase the existing value use pass a SDF::Null object to SetValue(). Note:

In PDF, Field's value is separate from its annotation (i.e. how the field appears on the page). After you modify Field's value you need to refresh Field's appearance using RefreshAppearance() method.

Alternatively, you can delete "AP" entry from the Widget annotation and set "NeedAppearances" flag in AcroForm dictionary (i.e. doc.GetAcroForm().Put("NeedAppearances", Obj.CreateBool(true)); ) This will force viewer application to auto-generate new field appearances every time the document is opened.

Yet another option is to generate a custom annotation appearance using ElementBuilder and ElementWriter and then set the "AP" entry in the widget dictionary to the new appearance stream. This functionality is useful in applications that need advanced control over how the form fields are rendered.

Returns:
A promise that resolves to an object of type: "PDFNet.ViewChangeCollection"
Type
Promise.<Core.PDFNet.ViewChangeCollection>

setValueAsBool(value)

sets the value of a check-box or radio-button field.
Parameters:
Name Type Description
value boolean If true, the filed will be set to 'True', if false the field will be set to 'False'. Note: This method is usually for check-box and radio button fields.
Returns:
A promise that resolves to an object of type: "PDFNet.ViewChangeCollection"
Type
Promise.<Core.PDFNet.ViewChangeCollection>

setValueAsString(value)

sets the value of the field (i.e. the value of the field's /V key). The format of field's value varies depending on the field type.
Parameters:
Name Type Description
value string the new field value. Note: in order to remove/erase the existing value use pass a SDF::Null object to SetValue(). Note:

In PDF, Field's value is separate from its annotation (i.e. how the field appears on the page). After you modify Field's value you need to refresh Field's appearance using RefreshAppearance() method.

Alternatively, you can delete "AP" entry from the Widget annotation and set "NeedAppearances" flag in AcroForm dictionary (i.e. doc.GetAcroForm().Put("NeedAppearances", Obj.CreateBool(true)); ) This will force viewer application to auto-generate new field appearances every time the document is opened.

Yet another option is to generate a custom annotation appearance using ElementBuilder and ElementWriter and then set the "AP" entry in the widget dictionary to the new appearance stream. This functionality is useful in applications that need advanced control over how the form fields are rendered.

Returns:
A promise that resolves to an object of type: "PDFNet.ViewChangeCollection"
Type
Promise.<Core.PDFNet.ViewChangeCollection>

useSignatureHandler(signature_handler_id)

Sets the signature handler to use for adding a signature to this field. If the signature handler is not found in PDFDoc's signature handlers list, this field will not be signed. To add signature handlers, use PDFDoc.AddSignatureHandler method. If a signature handler is already assigned to this field and this method is called once again, the associate signature handler for this field will be updated with the new handler.
Parameters:
Name Type Description
signature_handler_id number The unique id of the SignatureHandler to use for adding signature in this field.
Returns:
A promise that resolves to the signature dictionary created using the SignatureHandler, or NULL pointer if the signature handler is not found.
Type
Promise.<Core.PDFNet.Obj>