GridView Problem

Hi All,
I have a Gridview and inside that grid view i have some link. Now when i click on the link inside GridView i want to open an URL. I have written the event in RowCommand event of the GridView and i am getting URL value also. But URL is not opening in first time i click on the link only second time i click on the link its opening,

I want it to open in first click. I am using C# with asp.net

eg:

GridView1_RowCommand() {     string url=www.xyz.com     if (url != "")         {                                     GridView1.Attributes.Add("onclick", "window.open('" + url + "')");         } }