RadGrid inside a RadWindow, issue with NavigateURL

Hello Eyup,

Thank you, I made that change but still it doesnt work 

 I am having this weird issue with Radwindows navigateurl property 

When I do something like this it redirects

 <telerik:RadWindow ID="Details" Modal="true" Skin="MetroTouch" runat="server" Width="800px" Height="800px" Title="Details" CssClass="override" NavigateUrl="~/Details.aspx'" ></telerik:RadWindow>

But when I do it through the code behind it doesnt redirect to that page 

  protected void RadGrid1_ItemCommand(object source, GridCommandEventArgs e)
        {
            if (e.Item is GridDataItem)
            {
                GridDataItem item = (GridDataItem)e.Item;
                string value = item["Name"].Text;

                switch (e.CommandName)
                {
                    case "download": download(value);
                        break;
                    case "details": Details(value);
                        break;
                    case "sendemail": sendemail(value);
                        break;
                }
            }
        }

 private void Details(string Name)
        {            
            
            string script = "function f(){$find(\"" + Details.ClientID + "\").show(); Sys.Application.remove_load(f);}Sys.Application.add_load(f);";
            ScriptManager.RegisterStartupScript(Page, Page.GetType(), "key", script, true);
            string url = "details.aspx?name=" + Name;
            Details.NavigateUrl = url;         
          
        }