Sign documents with exception handling Leave feedback

GroupDocs.Signature provides different error messages due to validation issues, missing required data, files etc. For exception class GroupDocsSignatureException is being used.

Here are the steps to handle exceptions from GroupDocs.Signature:

• Compose try-catch block above Sign method with catching GroupDocsSignatureException type error.

This example shows how to handle GroupDocs.Signature exceptions.

try
{
    using (Signature signature = new Signature("sample.xlsx"))
    {
        DigitalSignOptions options = new DigitalSignOptions()
        {
            CertificateFilePath = Constants.CertificatePfx,
            ImageFilePath = Constants.ImageHandwrite,
            // skip password specification
            //Password = "123456780"
        };
        // sign document to file
        signature.Sign("signed.xlsx", options);
    }
}
catch (GroupDocsSignatureException ex)
{
    Console.WriteLine("GroupDocs Signature Exception: " + ex.Message);
}
catch (Exception ex)
{
    Console.WriteLine("System Exception: " + ex.Message);
}

Starting with GroupDocs.Signature for .NET 26.9, Sign also throws GroupDocsSignatureException when the signing certificate has expired or is not valid yet, and nothing is signed or saved. See “Certificates outside their validity period” in Pdf Digitally signing for the message and for the AllowExpired and AllowNotYetValid properties that allow such a certificate.

Sign also throws when the time-stamp authority set in PdfDigitalSignature.TimeStamp cannot be reached or rejects the request. See Sign PDF document with a time stamp.

You may easily run the code above and see the feature in action in our GitHub examples:

• GroupDocs.Signature for .NET examples, plugins, and showcase
• GroupDocs.Signature for Java examples, plugins, and showcase
• Document Signature for .NET MVC UI Example
• Document Signature for .NET App WebForms UI Example
• Document Signature for Java App Dropwizard UI Example
• Document Signature for Java Spring UI Example

Along with the full-featured .NET library, we provide simple but powerful free online apps.

To sign PDF, Word, Excel, PowerPoint, and other documents you can use the online apps from the GroupDocs.Signature App Product Family.