In Crystal reports.NET or Java application development, Crystal report viewer plays a vital role and is the only control which views a Crystal report. This blog provides few guidelines on how to use, customize the viewer and how to deal with viewer related (report viewing) issues. What is ‘CrystalReportViewer’ control and how to use it? The CrystalReportViewer control is used in the.NET Framework to bind to and display reports. The default CrystalReportViewer control includes UI elements to assist in viewing, saving and navigating through a report.