使用Http请求获取web页面源码

   下面的GetText函数获取网络请求的应答字符串，如gettext("http://www.baidu.com")返回百度页面的源文件。

    Shared Function GetText(ByVal Uri As String) As String

        Try

            Dim oWebReq As WebRequest = System.Net.WebRequest.Create(Uri)

            Dim oWebRep As WebResponse = oWebReq.GetResponse

            Dim sR As StreamReader = New StreamReader(oWebRep.GetResponseStream, Encoding.Default)

            Return sR.ReadToEnd

        Catch ex As Exception

            Return ""

        End Try

End Function