This example is outdated, you can check out the many other new examples in this category.This sample project demonstrates how to show report in the viewer. First of all, use Load method to load a report file:
 private void buttonControl_Click(object sender, EventArgs e)
{
	var report = new StiReport();
	report.Load(@"Reports\SimpleList.mrt");
	report.Render();
	stiViewerControl1.Report = report;
}

...

Next, use Show method to show report in the viewer:
...

private void buttonDialog_Click(object sender, EventArgs e)
{
	var report = new StiReport();
	report.Load(@"Reports\SimpleList.mrt");
	report.Show();
	//report.ShowWithRibbonGUI();
}

In the screenshot below you can see the result of the sample code:

Showing a Report in the Viewer
Hi. Need any help?