PdfDocument searchDocument = PdfDocument.Load(pdfFile);
                        PdfTypeIndirect indirectThing = (PdfTypeIndirect)searchDocument.Root.GetBy("PageLabels");
                        PdfTypeDictionary pageLabels = (PdfTypeDictionary)indirectThing.Direct;

                        foreach (PdfTypeBase theValue in pageLabels.Values)
                        {
                            PdfTypeArray ofCourseTheresAnotherArray = (PdfTypeArray)theValue;
                            foreach (var thing in ofCourseTheresAnotherArray)
                            {
                                if (thing is PdfTypeDictionary)
                                {
                                    PdfTypeDictionary anotherDictionary = (PdfTypeDictionary)thing;
                                    foreach (PdfTypeBase andWhyIsThereAnotherDictionary in anotherDictionary.Values)
                                    {
                                        if (andWhyIsThereAnotherDictionary is PdfTypeString)
                                        {
                                            string sheetLabel = ((PdfTypeString)andWhyIsThereAnotherDictionary).UnicodeString;
                                            if (sheetLabel.ToUpper().Contains(drawingTextBox.Text.ToUpper()))
                                            {
                                                foundFilesListView.Items.Add(pdfFile);
                                            }
                                        }
                                    }

                                }
                            }
                        }                            
                            
                        searchDocument.Dispose();