DataSource Controls :: Use Webconfig Connectionstring In Reportviewer?

In my project i use in webconfig

<appSettings> add
key="ConnectionString"
value="server=192.168.0.1;database=database;uid=usr;pwd=;"/>
</appSettings>

Use this key on .vb page -

Public constr As
String = ConfigurationSettings.AppSettings("ConnectionString")
dim cnn As new SqlConnection(constr)

Now i need to create conditional report where user select parameters from Dropdownlist and based on that Report is generate on web page. I tried so much with the help of

http://www.aspfree.com/c/a/ASP.NET/Binding-Data-to-the-ReportViewer-Control-Dynamically-in-ASPNET-20/1/ article but noluck. The data is display when i select the SELECT query from wizard while add dataset, but i want to do it dynamically coz webserver is located somewher else. Configuration is MSSQL server 2000, W2K3, VS 2005 Professional.

I did a Crystalreport projects with vb6 with ado but i really dont know how to exactly dynamically generate conditional report in Reportviewer.