如何使用HTMLAgilityPack解析HTML

Question

我想从该网站（http://www.mgm.gov.tr/?il=Bursa）获取天气数据。我用这个代码

Dim Web As New HtmlAgilityPack.HtmlWeb
    Dim Doc As New HtmlAgilityPack.HtmlDocument
    Doc = Web.Load("http://www.mgm.gov.tr/?il=Bursa")
    For Each endeks1 As HtmlAgilityPack.HtmlNode In Doc.DocumentNode.SelectNodes("//*[@id='t4']/div/div[1]/div[4]/span[1]")
        MessageBox.Show(endeks1.InnerText, "oksd", MessageBoxButtons.OK)
    Next

但是当我开始我的项目时出现问题 myscreen我该如何解决这个问题？