/// <summary>
/// 同步方式发起http post请求
/// </summary>
/// <param name="url">请求URL</param>
/// <param name="queryString">参数字符串</param>
/// <param name="errorMsg">返回错误信息.</param>
/// <param name="headers">需要传输的Header信息.</param>
/// <param name="encode">编码格式.</param>
/// <returns>
/// 请求返回值
/// </returns>
/// <remarks>
/// <list>
/// <item><description>添加Headers参数 modifyby Shaipe 2018/9/25</description></item>
/// </list>
/// </remarks>
public static string HttpPost(string url, string queryString, out string errorMsg, NameValueCollection headers = null, string encode = "UTF-8")
{
errorMsg = string.Empty;
string referer = "";
//if (HttpContext.Current != null && HttpContext.Current.Request != null)
//{
// referer = HttpContext.Current.Request.Url.AbsoluteUri;
//}
NetResponse response = new NetRequest().Post(url, queryString, referer, out errorMsg);
return(response.Content);
}