There is also itextsharp-lgpl. This will get the number of pages for you and the creation date. Sorry, no error checking, just bare bones.
/*/ nuget PDF\iTextSharp-LGPL; /*/
using iTextSharp.text;
using iTextSharp.text.pdf;
string inpath = @"C:\Users\Your_User\Documents\LibreAutomate\Documents\Your_Test_Dummy.pdf";
FileInfo file = new FileInfo(inpath);
// string name = file.Name.Substring(0, file.Name.LastIndexOf("."));
PdfReader reader = new PdfReader(inpath);
var info = reader.Info;
DateTime creationDate = PdfDate.Decode(info["CreationDate"].ToString());
// print.it(info); // for reference
// print.it(info["CreationDate"]); // for reference
print.it("Pdf created: " + creationDate);
print.it("Number of pages: " + reader.NumberOfPages);
reader = null;
Possible to get pdf page count?