If you run the application after adding a C1ReportViewer control to your application, you'll see an empty C1ReportViewer on the page. The next step is to invoke the C1ReportViewer.LoadDocument method to add some content to the control. The C1ReportViewer.LoadDocument method allows you to load content from Stream objects (which may contain PDF, HTML, or MHTML documents), or from strings (which may contain HTML or MHTML documents).