c#專案中用到呼叫客戶介面，basic身份認證，base64格式加密（使用者名稱:密碼）貼上程式碼以備後用

1、使用HttpClient實現basic身份認證

using (HttpClient client = new HttpClient())
            {
                client.DefaultRequestHeaders.Authorization=new AuthenticationHeaderValue("Basic", Convert.ToBase64String(Encoding.UTF8.GetBytes($"{Username}:{Password}")));
                HttpContent httpContent = new StringContent("", Encoding.UTF8);
                httpContent.Headers.ContentType = new MediaTypeHeaderValue("application/json");
                Uri address = new Uri("介面地址");
                var response = client.PostAsync(address, httpContent).Result.Content.ReadAsStringAsync().Result;//返回值
            }

2、使用HttpWebRequest實現basic身份認證

HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create("介面地址");
            request.Method = "Post";
            request.CookieContainer = new CookieContainer();
            request.ContentType = "application/json;";

            （1）設定請求Credentials
            CredentialCache credentialCache = new CredentialCache();
            credentialCache.Add(new Uri("介面地址"),"Basic", new NetworkCredential("bayer_rx", "bayerClientSecret"));
            request.Credentials = credentialCache;

            （2）設定Headers Authorization
            request.Headers.Add("Authorization", "Basic "+Convert.ToBase64String(Encoding.UTF8.GetBytes($"{Username}:{Password}")));
            using (HttpWebResponse response = (HttpWebResponse) request.GetResponse())
            {
                using (StreamReader reader = new StreamReader(response.GetResponseStream()))
                {
                    string content = reader.ReadToEnd();
                }
            }