Following is the sample code you can use to parse your querystring and return NameValueCollection
protected void Page_Load(object sender, EventArgs e)
{
String currurl = HttpContext.Current.Request.RawUrl;
String querystring = null ;
// Check to make sure some query string variables
// exist and if not add some and redirect.
int iqs = currurl.IndexOf(‘?’);
if (iqs == -1)
{
String redirecturl = currurl + “?var1=1&var2=2+2%2f3&var1=3″;
Response.Redirect(redirecturl, true);
}
// If query string variables exist, put them in
// a string.
else if (iqs >= 0)
{
querystring = (iqs < currurl.Length – 1) ? currurl.Substring(iqs + 1) : String.Empty;
}
// Parse the query string variables into a NameValueCollection.
NameValueCollection qscoll = HttpUtility.ParseQueryString(querystring);
// Iterate through the collection.
StringBuilder sb = new StringBuilder(“”);
foreach (String s in qscoll.AllKeys)
{
sb.Append(s + ” – ” + qscoll[s] + “”);
}
// Write the result to a label.
ParseOutput.Text = sb.ToString();
}
This is the front end code ,
<form id=”form1″ runat=”server”>
Query string variables are:
<asp:label id=”ParseOutput” runat=”server”>
</asp:label></form>
Hope this Helps 
