What implements IFormFieldObject in IronPDF?

Concrete implementors of IFormFieldObject in IronPDF include CheckboxFormField, ComboboxFormField, ImageFormField, RadioFormField, SignatureFormField. Code that accepts IFormFieldObject works uniformly across all implementors, with a cast to the concrete type only required when type-specific behavior is needed.

How do you use IFormFieldObject in C# code?

Accept IFormFieldObject as a parameter or return type in C# code that needs to work uniformly across IronPDF implementors. The interface defines the contract; concrete behavior is provided by the implementor returned at runtime.

What is the difference between IFormFieldObject and a concrete implementor?

IFormFieldObject is the interface contract; its concrete implementors carry the actual behavior. Reference IFormFieldObject when writing code that should work across multiple implementors; use a concrete type when a single implementor's behavior is required.

Where does IFormFieldObject live in the IronPDF API?

IFormFieldObject is in the IronSoftware.Forms namespace, shipped in IronPdf.dll. It extends IPdfDocumentObject. Concrete classes such as CheckboxFormField, ComboboxFormField implement it.

Interface IFormFieldObject

Form field object

Inherited Members

IPdfDocumentObject.Client

Namespace: IronSoftware.Forms

Assembly: IronPdf.dll

Syntax

public interface IFormFieldObject : IPdfDocumentObject

Working with PDF forms through a shared contract runs through IFormFieldObject. It represents form field object, so code can work with PDF forms uniformly across implementors rather than binding to a concrete type.

Concrete implementors include CheckboxFormField, ComboboxFormField, ImageFormField. Code that accepts IFormFieldObject works uniformly across these implementors, so applications can read or configure C# PDF features without binding to a specific concrete type.

Most of the usable surface is inherited. The members that carry everyday use of this contract are Client, Annotations, Choices, DefaultAppearance; consult these first when implementing or consuming IFormFieldObject.

using IronPdf;

// IFormFieldObject is consumed as the API surface for the family of implementors
void Consume(IFormFieldObject target)
{
    // Use members defined on the interface; concrete behavior follows the implementor
}

For collection-wide operations and end-to-end examples, see the IronPDF C# documentation for related guides. For collection-wide operations on IFormFieldObject instances, the IronPDF C# documentation lists the relevant container types and their methods. Concrete behavior depends on which implementor of IFormFieldObject is returned at runtime; consult the specific class reference for type-specific members. Polymorphic access through IFormFieldObject lets code work uniformly across the family of implementors, with a cast required only when type-specific behavior is needed. The reference tables below list the full set of members defined on IFormFieldObject along with any inherited members exposed through the contract. In a typical IronPDF C# workflow, IFormFieldObject appears as a parameter or return type at the boundary between the application and the IronPDF API. See the methods table below for the complete set of members defined directly on IFormFieldObject. Implementing IFormFieldObject directly in application code is uncommon; the typical pattern is to consume instances returned from the IronPDF API. When iterating over a collection of IFormFieldObject instances, prefer the inherited members for portable code; downcast only when type-specific behavior is required.

Properties

Annotations

Form field annotations

Declaration

List<IFormFieldAnnotation> Annotations { get; }

Property Value

Type	Description
System.Collections.Generic.List<IFormFieldAnnotation>

Choices

Selection choices

Declaration

List<string> Choices { get; }

Property Value

Type	Description
System.Collections.Generic.List<System.String>

DefaultAppearance

Default appearance string

Declaration

string DefaultAppearance { get; }

Property Value

Type	Description
System.String

FormFlags

Form field flags

Declaration

PdfFormFieldFlags FormFlags { get; }

Property Value

Type	Description
PdfFormFieldFlags

FormType

Form type

Declaration

string FormType { get; }

Property Value

Type	Description
System.String

FullName

Fully qualified name

Declaration

string FullName { get; }

Property Value

Type	Description
System.String

MaxLength

Maximum number of characters which can be specified in the value

Declaration

int MaxLength { get; set; }

Property Value

Type	Description
System.Int32

Name

Partial name

Declaration

string Name { get; set; }

Property Value

Type	Description
System.String

ObjType

Object type

Declaration

string ObjType { get; }

Property Value

Type	Description
System.String

ReadOnly

True if read-only

Declaration

bool ReadOnly { get; set; }

Property Value

Type	Description
System.Boolean

RichText

Form value using rich text

Declaration

string RichText { get; set; }

Property Value

Type	Description
System.String

Type

Pdf form field type

Declaration

PdfFormFieldType Type { get; }

Property Value

Type	Description
PdfFormFieldType

Value

Form value

Declaration

string Value { get; set; }

Property Value

Type	Description
System.String

Inherited members

Client