Cacher is the code snippet organizer for pro developers

// For complete examples and data files, please go to https://github.com/groupdocs-watermark/GroupDocs.Watermark-for-.NET
using (Document doc = Document.Load(Utilities.MapSourceFilePath (PptFilePath)))
{
    // Search by exact string
    TextSearchCriteria textSearchCriteria = new TextSearchCriteria("© 2017");

    // Find all possible watermarks containing some specific text
    PossibleWatermarkCollection possibleWatermarks = doc.FindWatermarks(textSearchCriteria);

}