c#, LicenseKey.LoadLicenseFile failing, System.NullReferenceException: 'Object reference not set to an instance of an object.'

Question

I am testing Itext7 for a C# project and when I try to load the license file, I get System.NullReferenceException: 'Object reference not set to an instance of an object.' I have already installed itext.licensekey,itext.licensekey.volume and itext.licensing.base.

I am using a 30 days trial license since I am still testing itext.

my code

LicenseKey.LoadLicenseFile(@"c:\temp\d521a5025706b32fe2c0d553d6e5e5eb72b3dbe708fed49e500c50670e8b1fdb.json");

        var pdf = File.ReadAllBytes(@"C:\temp\401239.pdf");

        PdfDocument pdfDoc = new PdfDocument(new PdfReader(@"C:\temp\401239.pdf"), new PdfWriter(@"C:\temp\new_401239.pdf"));
        Document document = new Document(pdfDoc);

        var documentInfo = pdfDoc.GetDocumentInfo();

        documentInfo.SetTitle("Test title");
        documentInfo.SetSubject("Subject");
        documentInfo.AddModDate();
        documentInfo.SetMoreInfo("File_Changed", "Test");


        document.Close();

        

        PdfOptimizer optimizer = new PdfOptimizer();

        optimizer.AddOptimizationHandler(new FontDuplicationOptimizer());
        optimizer.AddOptimizationHandler(new CompressionOptimizer());

        ImageQualityOptimizer jpeg_optimizer = new ImageQualityOptimizer();
        jpeg_optimizer.SetJpegProcessor(new JpegCompressor(.5f));
        optimizer.AddOptimizationHandler(jpeg_optimizer);

        optimizer.Optimize(
                new FileInfo(@"C:\temp\new_401239.pdf"),
                new FileInfo(@"C:\temp\opt_401239.pdf"));

Any help would be greatly appreciated.

Expecting itext7 license file loaded.

Answer 1

install this

dotnet add package itext.licensing.base --version 4.1.4

and put this line in your program

LicenseKey.LoadLicenseFile(@"c:\temp\d521a5025706b32fe2c0d553d6e5e5eb72b3dbe708fed49e500c50670e8b1fdb.json");