Open PDF file through windows application

A non-embedded solution (i.e. not a control put into your own UI) is get Windows to "run" the PDF file, which will open the PDF file with the user's default PDF application handler (similar to what would happen had the user "double-clicked" on the PDF file to open it).

The benefit of doing it this way is that the user can choose what application to use for PDFs (by setting their preferred PDF-capable application as the default for opening a PDF file) and also means that your application will no longer depend directly on Adobe Acrobat Reader.

// Code snippet...
string pdfFilePath= "C:\MyLocation\My.pdf";

var start = System.Diagnostics.Process.Start(pdfFilePath);
start.EnableRaisingEvents = true;
start.Exited += delegate (object sender, EventArgs e)
{
    // You can even do something when the PDF application closes
}

Of course this depends on whether you can change your requirements to not require embedding a PDF viewing control within your application.