方案1：
/// <summary >
/// 传入URL返回网页的html代码
/// </summary >
/// <param name="Url" >URL </param >
/// <returns > </returns >
public static string getUrltoHtml(string Url)
{
errorMsg = "";
try
{
System.Net.WebRequest wReq = System.Net.WebRequest.Create(Url);
// Get the response instance.
System.Net.WebResponse wResp =wReq.GetResponse();
// Read an HTTP-specific property
//if (wResp.GetType() ==HttpWebResponse)
//{
//DateTime updated =((System.Net.HttpWebResponse)wResp).LastModified;
//}
// Get the response stream.
System.IO.Stream respStream = wResp.GetResponseStream();
// Dim reader As StreamReader = New StreamReader(respStream)
System.IO.StreamReader reader = new System.IO.StreamReader(respStream, System.Text.Enco
