XmlDocument xmlVerisi = new XmlDocument();
xmlVerisi.Load("http://www.tcmb.gov.tr/kurlar/today.xml");
decimal dolar = Convert.ToDecimal(xmlVerisi.SelectSingleNode(string.Format("Tarih_Date/Currency[@Kod='{0}']/ForexSelling", "USD")).InnerText.Replace('.',','));

decimal Euro = Convert.ToDecimal(xmlVerisi.SelectSingleNode(string.Format("Tarih_Date/Currency[@Kod='{0}']/ForexSelling", "EUR")).InnerText.Replace('.', ','));

Label1.Text = dolar.ToString(); 8 Label2.Text = Euro.ToString();
Label2.Text = Euro.ToString();