c# 发送web请求

我们目前涉及到的现有的接收请求方式有三种，

第一种：

页面式的Form表单

第二种：

服务的webservice形式的xml

第三个：

restful风格的post包体json

第一种比较老，博客园的登录就是这样的。找了个例子

这里不做具体讨论了。

例子

List<KeyValuePair<string, string>> paramList = new List<KeyValuePair<string, string>>();
                HttpClient _client = new HttpClient();

                async void DownloadPageAsync()
                {
                    // Use static HttpClient to avoid exhausting system resources for network connections.
                    var result = await _client.PostAsync(new Uri(url), new FormUrlEncodedContent(paramList));
                    // Write status code.
                    Console.WriteLine("STATUS CODE: " + result.StatusCode);
                    result.EnsureSuccessStatusCode();
                    string resultStr = await result.Content.ReadAsStringAsync();
                    Console.WriteLine(resultStr);
                }
                DownloadPageAsync();

第二种的，webservice的，之前的博客里有。

参考

第三种，比较新的json的请求方式

针对这种，就只能用json字符串来提交了，具体代码是

string url = getPRC_Url(serviceName, apiName, null);
string body = "{";
//如果需要POST数据   
if (!(parameters == null || parameters.Count == 0))
{
    StringBuilder buffer = new StringBuilder();
    foreach (string key in parameters.Keys)
    {
        buffer.AppendFormat(""{0}":"{1}",", key, parameters[key]);
    }
    body += buffer.ToString() + "}";
}
try
{
    HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(url);
    httpWebRequest.ContentType = "application/json";
    httpWebRequest.Method = "POST";
    httpWebRequest.Timeout = 20000;
    byte[] btBodys = Encoding.UTF8.GetBytes(body);
    httpWebRequest.ContentLength = btBodys.Length;
    httpWebRequest.GetRequestStream().Write(btBodys, 0, btBodys.Length);
    HttpWebResponse httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();
    StreamReader streamReader = new StreamReader(httpWebResponse.GetResponseStream());
    string responseContent = streamReader.ReadToEnd();
    return responseContent;
}
catch (Exception ex)
{
    return null;
}

主要是这个入参需要放在包体里，并且得是"{}"形式的方可。