Class SignatureFormField

Inheritance
System.Object
SignatureFormField
Implements
IronSoftware.Abstractions.Pdf.IPdfDocumentObject
IronSoftware.Abstractions.IDocumentObject
Namespace: IronSoftware.Forms
Assembly: IronPdf.dll
Syntax
public class SignatureFormField : Object, IFormField, IFormFieldObject, IFormFieldAnnotationObject, IPdfDocumentObject

Working with PDF forms in IronPDF runs through SignatureFormField. It is part of the IronPDF PDF forms API.

SignatureFormField matters when an application needs to configure or invoke PDF forms from C# code. The class encapsulates the related options and behavior in a single object that is set up once and reused across render or processing calls. Typical scenarios include batch generation pipelines, templated document workflows, and integration with existing C# document services.

To use SignatureFormField, instantiate or obtain it from the relevant entry point in the IronPDF C# API. Key properties include Annotations, Choices, Client, DefaultAppearance. Assign options or invoke methods on the instance to configure or perform the operation. The create forms covers typical usage in C# end to end.

using IronPdf;

// Obtain SignatureFormField from the relevant entry point in the IronPDF API
void Configure(SignatureFormField instance)
{
    var current = instance.Annotations;
    instance.SetDefaultFont();
}

For the broader workflow, see the edit forms guide in the IronPDF C# documentation. For broader context, the PDF forms portion of the IronPDF C# API contains related types that work with SignatureFormField directly. SignatureFormField exposes additional members beyond those highlighted above; the reference tables on this page list the full set. In application code, treat SignatureFormField as a configured object that is constructed once and reused across operations rather than instantiated per call. Configuration is generally idempotent: assigning the same property value twice has the same effect as assigning it once. For diagnostic purposes, inspect the relevant SignatureFormField property after each operation to confirm the configured state. See the constructors, properties, and methods tables below for the complete API surface of SignatureFormField. Application code typically obtains or instantiates a single SignatureFormField and shares it across multiple IronPDF operations rather than recreating it per call.

Constructors

SignatureFormField(String, UInt32, Double, Double, Double, Double)

Create a new empty signature form field using the specified parameters

Declaration
public SignatureFormField(string name, uint page_index, double x, double y, double width, double height)
Parameters
Type Name Description
System.String name

Form name
System.UInt32 page_index

Form page index
System.Double x

Form x-coordinate
System.Double y

Form y-coordinate
System.Double width

Form width
System.Double height

Form height

Properties

Annotations

Declaration
public List<IFormFieldAnnotation> Annotations { get; protected set; }
Property Value
Type Description
System.Collections.Generic.List<IFormFieldAnnotation>

Choices

Selection choices

Declaration
public List<string> Choices { get; protected set; }
Property Value
Type Description
System.Collections.Generic.List<System.String>

Client

Pdf client

Declaration
public IPdfClient Client { get; set; }
Property Value
Type Description
IronSoftware.Pdfium.IPdfClient

DefaultAppearance

Declaration
public string DefaultAppearance { get; set; }
Property Value
Type Description
System.String

DocumentId

Declaration
public IDocumentId DocumentId { get; set; }
Property Value
Type Description
IronSoftware.Abstractions.Pdf.IDocumentId

FormFlags

Form field flags

Declaration
public PdfFormFieldFlags FormFlags { get; set; }
Property Value
Type Description
PdfFormFieldFlags

FormType

Form type

Declaration
public string FormType { get; }
Property Value
Type Description
System.String

FullName

Fully qualified name

Declaration
public string FullName { get; protected set; }
Property Value
Type Description
System.String

Height

Annotation height

Declaration
public double Height { get; set; }
Property Value
Type Description
System.Double

MaxLength

Maximum number of characters which can be specified in the value

Declaration
public int MaxLength { get; set; }
Property Value
Type Description
System.Int32

Name

Partial name

Declaration
public string Name { get; set; }
Property Value
Type Description
System.String

ObjNum

Declaration
public uint ObjNum { get; set; }
Property Value
Type Description
System.UInt32

ObjType

Object type

Declaration
public string ObjType { get; }
Property Value
Type Description
System.String

PageIndex

Declaration
public uint PageIndex { get; set; }
Property Value
Type Description
System.UInt32

ReadOnly

True if read-only

Declaration
public bool ReadOnly { get; set; }
Property Value
Type Description
System.Boolean

RichText

Declaration
public string RichText { get; set; }
Property Value
Type Description
System.String

Type

Pdf form field type

Declaration
public PdfFormFieldType Type { get; }
Property Value
Type Description
PdfFormFieldType

Value

Form value

Declaration
public string Value { get; set; }
Property Value
Type Description
System.String

Width

Annotation width

Declaration
public double Width { get; set; }
Property Value
Type Description
System.Double

X

Annotation X position

Declaration
public double X { get; set; }
Property Value
Type Description
System.Double

Y

Annotation y position

Declaration
public double Y { get; set; }
Property Value
Type Description
System.Double

Methods

SetDefaultFont(String, Int32, Color)

NOT SUPPORTED

Declaration
public void SetDefaultFont(string FontName, int FontSize, Color FontColor)
Parameters
Type Name Description
System.String FontName

n/a
System.Int32 FontSize

n/a
System.Drawing.Color FontColor

n/a
Exceptions
Type Condition
System.NotImplementedException

Signature form fields do not support setting of default font

Implements

IronSoftware.Abstractions.Pdf.IPdfDocumentObject
IronSoftware.Abstractions.IDocumentObject