PDFTron PDFNet must be initialized with a valid key exception

If you get an exception with a message like the following

This product must be initialized with a valid key

when you call

PDFNet.Initialize();

with no argument, then you need to apply either a demo key, or your purchased license key.

I am evaluating PDFTron

You should have already received a demo licence key.
Please see the getting started documentation that comes with the SDK you are evaluating.

If you are still stuck, please go to support.pdftron.com for further assistance.

The correct call should be something like the following.

PDFNet.Initialize("demo:name@your.domain:1d361cc1be2e40e1b57a2f759e7937301d361cc1be2e40e1b5");

I purchased PDFTron

The license key was emailed to the email addresses registered with PDFTron for your account, which may or may not be you. If you cannot find it please contact sales@pdftron.com to get the license key re-sent.

The correct call should be something like the following.

PDFNet.Initialize("MyCompany:OEM:1234");