如何在iText7 v8.0.3中创建PDF签名域？

iText7 8.x版本对表单域相关API做了重构，原PdfFormField.CreateSignature方法已被移除，需要改用PdfSignatureFormField类来创建签名域。

修改后的签名域创建代码 #

替换你原代码中创建签名域的部分为以下内容：

// Add signature field
PdfAcroForm form = PdfAcroForm.GetAcroForm(pdf, true);
// 使用PdfSignatureFormField构造方法创建签名域
PdfSignatureFormField signatureField = new PdfSignatureFormField(pdf, new Rectangle(100, 100, 200, 50));
signatureField.SetFieldName("Signature");
// 可选：添加签名提示文本（默认显示"Click here to sign"）
signatureField.SetValueAsString("请在此处签名");
form.AddField(signatureField);

完整修改后的代码 #

public async Task<FileStreamResult> DownloadPropertyList(LDSC_DownloadParams downloadParams)
{
    Instance instance = await GetInstance(downloadParams.ImplementationId);

    // Create a new PDF document
    MemoryStream memoryStream = new MemoryStream();
    PdfWriter writer = new PdfWriter(memoryStream);
    writer.SetCloseStream(false);
    PdfDocument pdf = new PdfDocument(writer);
    Document document = new Document(pdf);

    // Create a table with a column for each property attribute
    Table table = new Table(UnitValue.CreatePercentArray(new float[] { 20, 20, 20, 10, 10, 20 }))
        .UseAllAvailableWidth();

    // Add headers to the table
    table.AddHeaderCell("Property Name");
    table.AddHeaderCell("Address");
    table.AddHeaderCell("City");
    table.AddHeaderCell("State");
    table.AddHeaderCell("Zip Code");
    table.AddHeaderCell("Contact");

    // Iterate over ScreeningProperties and add rows to the table
    foreach (var property in instance.ScreeningProperties)
    {
        table.AddCell(property.PropertyName ?? "");
        table.AddCell(property.Address ?? "");
        table.AddCell(property.City ?? "");
        table.AddCell(property.State?.ToString() ?? "");
        table.AddCell(property.ZipCode ?? "");
        table.AddCell($"{property.ContactPerson ?? ""}\n{property.PhoneNumber ?? ""}");
    }

    // Add the table to the document
    document.Add(table);

    // Add signature field - 修改后的代码
    PdfAcroForm form = PdfAcroForm.GetAcroForm(pdf, true);
    PdfSignatureFormField signatureField = new PdfSignatureFormField(pdf, new Rectangle(100, 100, 200, 50));
    signatureField.SetFieldName("Signature");
    signatureField.SetValueAsString("请在此处签名"); // 可选提示文本
    form.AddField(signatureField);

    // Close the document
    document.Close(); // This finalizes the document and writes it to the memory stream

    // Prepare the memory stream to be returned
    memoryStream.Position = 0;

    // Return the FileStreamResult
    // Adjust the file name as needed
    return new FileStreamResult(memoryStream, "application/pdf")
    {
        FileDownloadName = "PropertyList.pdf"
    };
}

关键说明 #

• PdfSignatureFormField是iText7 8.x中专门用于创建签名域的类，构造方法需要传入PdfDocument和签名域的矩形区域（位置和大小）
• 可以通过SetValueAsString设置签名域的提示文本，用户未签名时会显示该文本
• 其他表单域的操作逻辑保持不变，仅替换签名域的创建方式即可

内容的提问来源于stack exchange，提问作者user1274820