发送Web请求 ，GET请求和POST请求
/// <summary>
/// 发送GET请求
/// </summary>
/// <param name="url"></param>
/// <returns></returns>
public static string Webrequest(string url)
{
WebRequest wr = WebRequest.Create(url);
wr.Credentials = CredentialCache.DefaultCredentials;
wr.Method = "GET";
wr.ContentType = "application/x-www-form-urlencoded";
WebResponse response = wr.GetResponse();
Stream dataStream = response.GetResponseStream();
// Open the stream using a StreamReader for easy access.
StreamReader reader = new StreamReader(dataStream);
// Read the content.
string responseFromServer = reader.ReadToEnd();
reader.Close();
dataStream.Close();
response.Close();
return responseFromServer;
}
/// <summary>
/// POST请求
/// </summary>
/// <param name="url"></param>
/// <param name="postdata">二进制后的参数</param>
/// <returns></returns>
public static string Webrequest(string url, byte[] postdata)
{
WebRequest wr = WebRequest.Create(url);
wr.Credentials = CredentialCache.DefaultCredentials;
wr.Method = "POST";
wr.ContentType = "application/x-www-form-urlencoded";
wr.ContentLength = postdata.Length;
Stream sw = wr.GetRequestStream();
sw.Write(postdata, 0, postdata.Length);
sw.Close();
WebResponse response = wr.GetResponse();
Stream dataStream = response.GetResponseStream();
// Open the stream using a StreamReader for easy access.
StreamReader reader = new StreamReader(dataStream, Encoding.Default);
// Read the content.
string responseFromServer = reader.ReadToEnd();
reader.Close();
dataStream.Close();
response.Close();
return responseFromServer;
}比较简单的Web请求（get/post）方法封装，调用网络接口时能用到
原文：http://blog.csdn.net/w5762/article/details/42456773
