C#调用web api要不要考虑跨域？

[-一个大坑]

       string url = "http:*******/QueryMileage";
       string param = "param={'regNO':['粤TSW364'],'begin':'2017-06-10 10:03:15','end':'2017-06-10 12:03:15'}";;
        string result = request(url, param);

        public string request(string url, string param)
        {
            string strURL = url + '?' + param;
            System.Net.HttpWebRequest request;
            request = (System.Net.HttpWebRequest)WebRequest.Create(strURL);
            request.Method = "POST";
            System.Net.HttpWebResponse response;
            response = (System.Net.HttpWebResponse)request.GetResponse();
            System.IO.Stream s;
            s = response.GetResponseStream();
            string StrDate = "";
            string strValue = "";
            StreamReader Reader = new StreamReader(s, Encoding.UTF8);
            while ((StrDate = Reader.ReadLine()) != null)
            {
                strValue += StrDate + "\r\n";
            }
            return strValue;
        }

总是提示无法连接到服务器

[-一个大坑]

使用Post方式调用Web Service，需要在服务项目配置文件Web.config中添加使用Http协议的配置，在<system.web>标签中添加<webServices> <protocols> <add name= "HttpPost"/></protocols></webServices>配置 加了这个后现在报错变了 無效的 URI: 無法剖析 Authority/Host。

[by_封爱]

域是指不同域名之间相互访问. 也就是 如果你用js访问webapi的时候 会出现这种问题.. 但是用后台代码是不存在"跨域"的问题的. 至于你的错误...是你的POST请求方法有问题. 因为是POST最起码的 你不能把你的POST数据 扔URL上面吧... 那叫get...

public static string PostHttp(string url, string data, Dictionary<string, string> headers)
        {
            HttpWebRequest request = null;
            if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase))
            {
                ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);
                request = WebRequest.Create(url) as HttpWebRequest;
                request.ProtocolVersion = HttpVersion.Version11;
            }
            else
            {
                request = WebRequest.Create(url) as HttpWebRequest;
            }
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";
            request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";
            request.Timeout = 5000;
            foreach (var item in headers)
            {
                request.Headers.Add(item.Key, item.Value);
            }
            byte[] postData = Encoding.ASCII.GetBytes(data);
            using (Stream stream = request.GetRequestStream())
            {
                stream.Write(postData, 0, postData.Length);
            }
            string msg = "";
            using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
            {
                using (StreamReader reader = new StreamReader(response.GetResponseStream()))
                {
                    msg = reader.ReadToEnd();
                }
            }
            return msg;
        }

[by_封爱]

另外 webapi跟webservice没任何关系.... 你的"服务端" 到底是什么 你自己知道吗??

[by_封爱]

我看了下LZ以前的帖子.. 我似乎发现 你连什么是get 什么是post好像还不是很清楚.....

[-一个大坑]

引用 4 楼 diaodiaop 的回复:

我看了下LZ以前的帖子.. 我似乎发现 你连什么是get 什么是post好像还不是很清楚.....

我一直以为get是直接查；post是传参然后接收返回值

[-一个大坑]

引用 2 楼 diaodiaop 的回复:

域是指不同域名之间相互访问. 也就是 如果你用js访问webapi的时候 会出现这种问题.. 但是用后台代码是不存在"跨域"的问题的. 至于你的错误...是你的POST请求方法有问题. 因为是POST最起码的 你不能把你的POST数据 扔URL上面吧... 那叫get...

public static string PostHttp(string url, string data, Dictionary<string, string> headers)
        {
            HttpWebRequest request = null;
            if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase))
            {
                ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);
                request = WebRequest.Create(url) as HttpWebRequest;
                request.ProtocolVersion = HttpVersion.Version11;
            }
            else
            {
                request = WebRequest.Create(url) as HttpWebRequest;
            }
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";
            request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";
            request.Timeout = 5000;
            foreach (var item in headers)
            {
                request.Headers.Add(item.Key, item.Value);
            }
            byte[] postData = Encoding.ASCII.GetBytes(data);
            using (Stream stream = request.GetRequestStream())
            {
                stream.Write(postData, 0, postData.Length);
            }
            string msg = "";
            using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
            {
                using (StreamReader reader = new StreamReader(response.GetResponseStream()))
                {
                    msg = reader.ReadToEnd();
                }
            }
            return msg;
        }

data是传参？headers是什么？CheckValidationResult是方法？没有

[-一个大坑]

和跨域没关系访问外网需要权限，申请权限就好了