Refresh required all the time? (ASP.NET)

[Bullfrog1870]

I have a simple report being displayed via ASP.NET in VB. Every time I hit a navigate button on the CRViewer toolbar the report disappears (no errors). I had to add the following code to my Page_Load routine to get the results I wanted.

If Page.IsPostBack Then
reportDocument1.Load(gstrReportDirectory & DropDownList1.SelectedValue & ".rpt")
CrystalReportViewer1.ReportSource = reportDocument1
reportDocument1.Refresh()
End If

Is this necessary or am I missing a setting somewhere? Seems like it would be smart enough to refresh on its own.

I'm confused!