使用activePDF Toolkit除了能實現PDF的轉換功能，還能創建數字簽名，而所有的這一切都只需要通過簡單的代碼設置就可以實現。

》》》下載activePDF Toolkit試用版

示例代碼如下：

// Copyright (c) 2013 activePDF, Inc.
// Example created 01/17/13
 
// Make sure to add the activePDF product .NET DLL(s) to your application.
// .NET DLL(s) are typically found in the products 'bin' folder.
 
class Examples
{
  public void main()
  {
    long certID;
    long CreateCertResult;
    string strPath;
    int intSignExistingField;
     
    strPath = AppDomain.CurrentDomain.BaseDirectory;
 
    // Instantiate Object
    APToolkitNET.Toolkit oTK = new APToolkitNET.Toolkit();
     
    // Find certificate, if it doesn't exist it will be created
    // If you have an existing signature you can find it with FindCertificate
    // and remove the portion of code that creates the certificate
    certID = oTK.FindCertificate("John Doe", "My", 1);
    if (certID < 1)
    {
      // Certificate not found, create a certificate with Toolkit
      CreateCertResult = oTK.CreateCertificate("John Doe", "Management", "Doe Enterprises", "Mission Viejo", "CA", "US", "john@doee.com", 1, "My", 365, 0, "", "");
      if (CreateCertResult == 1)
      {
        // New certificate created, find it for use
        certID = oTK.FindCertificate("John Doe", "My", 1);
        if (certID < 1)
        {
          ErrorHandler("FindCertificate", certID);
        }
      } else {
        // Create certificate failed
        ErrorHandler("CreateCertificate", CreateCertResult);
      }
    }
     
    // Sign an existing PDF containing a signature field
    intSignExistingField = oTK.SignExistingField(certID, strPath + "PDF(sigfield).pdf", strPath + "new.pdf", "SigField", "Mission Viejo, CA", "Security", "949-555-1212", "", 8, "Signed Document", "Helvetica", 12.0f, 1);
    if (intSignExistingField != 0)
    {
      ErrorHandler("SignExistingField", intSignExistingField);
    }
     
    // Release Object
    oTK = null;
     
    // Process Complete
    System.Diagnostics.Debug.WriteLine("Done!");
  }
   
  // Error Handling
  public static void ErrorHandler(string strMethod, object rtnCode)
  {
    System.Diagnostics.Debug.WriteLine(strMethod + " error:  " + rtnCode.ToString());
  }
}