Data Controls :: How To Export Gridview To Excel File

[URL] .... I use this article for exporting gridview to Excel in asp.net - c#.....but i found some error in my code

i am using stored procedure for sql command and my code behind is as follows....

C# code

public partial class Admin_ResultDisplay : System.Web.UI.Page {   
SqlConnection cn; protected void Page_Load(object sender, EventArgs e) {       
cn = new SqlConnection(ConfigurationManager.ConnectionStrings["DbConnect"].ConnectionString); 
//string strQuery = "select CustomerID,City,Country,PostalCode from customers"; 
//SqlCommand cmd = new SqlCommand(strQuery);       

[Code] ....

How can I pass sql command at page_load event ? ?