using System.Text;
using System.IO;
using System.Web.UI;

public string RenderControl(Control ctrl) 
{
    StringBuilder miaStringa = new StringBuilder();
    StringWriter miowriter = new StringWriter(miaStringa);
    HtmlTextWriter mioHtml = new HtmlTextWriter(miowriter);

    ctrl.RenderControl(mioHtml);
    return sb.ToString();
}

