Electronically Sign PDF Documents with Form Field Signatures using C#

ElectronicallySignPDF_CSharp.md

Learn how to electronically sign PDF documents with Form Field signatures using C#: https://blog.conholdate.com/2021/08/12/sign-pdf-with-form-field-signatures-using-csharp/

The following topics are discussed/covered in this article:

1. Sign PDF Documents with Form Field Signatures using C#

• Text Form Field Signatures
• Radio Button Form Field Signatures
• Combobox Form Field Signatures
• Checkbox Form Field Signatures
• Digital Form Field Signatures

2. Sign PDF Documents with Multiple Form Field Signatures using C#

ElectronicallySignPDF_CSharp_CheckboxFormFieldSignature.cs

// create an instance of Signature
Signature signature = new Signature(@"C:\Files\sample.pdf");

List<SignOptions> listOptions = new List<SignOptions>();

// instantiate text form field signature
CheckboxFormFieldSignature chbSignature = new CheckboxFormFieldSignature("chbData1", true);
// instantiate options based on text form field signature
FormFieldSignOptions optionsTextCHB = new FormFieldSignOptions(chbSignature);
optionsTextCHB.HorizontalAlignment = HorizontalAlignment.Center;
optionsTextCHB.VerticalAlignment = VerticalAlignment.Top;
optionsTextCHB.Margin = new Padding(20, 0, 270, 0);
optionsTextCHB.Height = 20;
optionsTextCHB.Width = 20;

// sign document to file
signature.Sign(@"C:\Files\CheckboxFormFieldSignature.pdf", optionsTextCHB);

ElectronicallySignPDF_CSharp_ComboboxFormFieldSignature.cs

// create an instance of Signature
Signature signature = new Signature(@"C:\Files\sample.pdf");

// instantiate combo box form field signature
List<string> items = new List<string>() { "Australia", "United Kingdom", "United States" };
ComboboxFormFieldSignature cmbSignature = new ComboboxFormFieldSignature("combo1", items, "Australia");
// instantiate options based on text form field signature
FormFieldSignOptions optionsTextCMB = new FormFieldSignOptions(cmbSignature);
optionsTextCMB.HorizontalAlignment = HorizontalAlignment.Center;
optionsTextCMB.VerticalAlignment = VerticalAlignment.Top;
optionsTextCMB.Margin = new Padding(20, 0, 238, 0);
optionsTextCMB.Height = 20;
optionsTextCMB.Width = 200;

// sign document to file
signature.Sign(@"C:\Files\ComboboxFormFieldSignature.pdf", optionsTextCMB);

ElectronicallySignPDF_CSharp_DigitalFormFieldSignature.cs

// create an instance of Signature
Signature signature = new Signature(@"C:\Files\sample.pdf");

// instantiate text form field signature
DigitalFormFieldSignature digSignature = new DigitalFormFieldSignature("dgData1");
// instantiate options based on text form field signature
FormFieldSignOptions optionsTextDIG = new FormFieldSignOptions(digSignature);
optionsTextDIG.HorizontalAlignment = HorizontalAlignment.Center;
optionsTextDIG.VerticalAlignment = VerticalAlignment.Top;
optionsTextDIG.Margin = new Padding(20, 0, 300, 0);
optionsTextDIG.Height = 50;
optionsTextDIG.Width = 200;
optionsTextDIG.ForeColor = System.Drawing.Color.Yellow;

// sign document to file
signature.Sign(@"C:\Files\DigitalFormFieldSignature.pdf", optionsTextDIG);

ElectronicallySignPDF_CSharp_FormFieldSignatures.cs

// create an instance of Signature
Signature signature = new Signature(@"C:\Files\sample.pdf");

List<SignOptions> listOptions = new List<SignOptions>();

// instantiate text form field signature
TextFormFieldSignature textSignature = new TextFormFieldSignature("tbData1", "Enter Your Name");
// instantiate options based on text form field signature
FormFieldSignOptions optionsTextFF = new FormFieldSignOptions(textSignature)
{
    HorizontalAlignment = HorizontalAlignment.Center,
    VerticalAlignment = VerticalAlignment.Top,
    Margin = new Padding(20, 0, 138, 0),
    Height = 20,
    Width = 200
};

// instantiate radio-button form field signature
List<string> radioOptions = new List<string>() { "Male", "Female" };
RadioButtonFormFieldSignature rbSignature = new RadioButtonFormFieldSignature("radioData1", radioOptions, "Male");
// instantiate options based on text form field signature
FormFieldSignOptions optionsTextRB = new FormFieldSignOptions(rbSignature)
{
    HorizontalAlignment = HorizontalAlignment.Center,
    VerticalAlignment = VerticalAlignment.Top,
    Margin = new Padding(20, 0, 170, 0),
    Height = 50,
    Width = 200,
};

// instantiate combo box form field signature
List<string> items = new List<string>() { "Australia", "United Kingdom", "United States" };
ComboboxFormFieldSignature cmbSignature = new ComboboxFormFieldSignature("combo1", items, "Australia");
// instantiate options based on text form field signature
FormFieldSignOptions optionsTextCMB = new FormFieldSignOptions(cmbSignature)
{
    HorizontalAlignment = HorizontalAlignment.Center,
    VerticalAlignment = VerticalAlignment.Top,
    Margin = new Padding(20, 0, 238, 0),
    Height = 20,
    Width = 200,
};

// instantiate text form field signature
CheckboxFormFieldSignature chbSignature = new CheckboxFormFieldSignature("chbData1", true);
// instantiate options based on text form field signature
FormFieldSignOptions optionsTextCHB = new FormFieldSignOptions(chbSignature)
{
    HorizontalAlignment = HorizontalAlignment.Center,
    VerticalAlignment = VerticalAlignment.Top,
    Margin = new Padding(20, 0, 270, 0),
    Height = 20,
    Width = 20,
};


// instantiate digital form field signature
DigitalFormFieldSignature digSignature = new DigitalFormFieldSignature("dgData1");
// instantiate options based on text form field signature
FormFieldSignOptions optionsTextDIG = new FormFieldSignOptions(digSignature)
{
    HorizontalAlignment = HorizontalAlignment.Center,
    VerticalAlignment = VerticalAlignment.Top,
    Margin = new Padding(20, 0, 300, 0),
    Height = 50,
    Width = 200,
};

// add form fields to sign options list
listOptions.Add(optionsTextFF);
listOptions.Add(optionsTextCHB);
listOptions.Add(optionsTextRB);
listOptions.Add(optionsTextCMB);
listOptions.Add(optionsTextDIG);

// sign document to file
signature.Sign(@"C:\Files\Signature\sample_output.pdf", listOptions);

ElectronicallySignPDF_CSharp_RadioButtonFormFieldSignature.cs

// create an instance of Signature
Signature signature = new Signature(@"C:\Files\sample.pdf");

// instantiate radio-button form field signature
List<string> radioOptions = new List<string>() { "Male", "Female" };
RadioButtonFormFieldSignature rbSignature = new RadioButtonFormFieldSignature("radioData1", radioOptions, "Male");
// instantiate options based on text form field signature
FormFieldSignOptions optionsTextRB = new FormFieldSignOptions(rbSignature);
optionsTextRB.HorizontalAlignment = HorizontalAlignment.Center;
optionsTextRB.VerticalAlignment = VerticalAlignment.Top;
optionsTextRB.Margin = new Padding(20, 0, 170, 0);
optionsTextRB.Height = 50;
optionsTextRB.Width = 200;

// sign document to file
signature.Sign(@"C:\Files\RadioButtonFormFieldSignature.pdf", optionsTextRB);

ElectronicallySignPDF_CSharp_TextFormFieldSignature.cs

// create an instance of Signature
Signature signature = new Signature(@"C:\Files\sample.pdf");

// instantiate text form field signature
TextFormFieldSignature textSignature = new TextFormFieldSignature("textBoxData1", "Enter Your Name");
// instantiate options based on text form field signature
FormFieldSignOptions optionsTextFF = new FormFieldSignOptions(textSignature);
optionsTextFF.HorizontalAlignment = HorizontalAlignment.Center;
optionsTextFF.VerticalAlignment = VerticalAlignment.Top;
optionsTextFF.Margin = new Padding(20, 0, 170, 0);
optionsTextFF.Height = 50;
optionsTextFF.Width = 200;

// sign document to file
signature.Sign(@"C:\Files\TextFormFieldSignature.pdf", optionsTextFF);