原本是在JavaScript中使用AJAX取回資料並做處理，再把處理過的資料跟表單一起送出，
但因為好像會有安全性的問題，改成在後端實作來達到一樣的效果，
有點不知道該怎麼註解，就先記錄下來

原本在前端呼叫所取回的資料：
{ "message": "檔案資訊", "files": [ { "Id": 123, "FileName": "測試圖.png", "CreateTime": "2020-05-25T14:25:44.857", "Status": "未掃毒" } ] }

需要用到的資料有"Id"跟"FileName"

在程式碼中加入類別，雖然不需用到"CreateTime"跟"Status"，但回傳多少欄位就要完整宣告

 public class JsonVO
 {
    public string message { get; set; }
    public List<files> files { get; set; }
 }
 
 public class files
 {
    public string Id { get; set; }
    public string FileName { get; set; }
    public string CreateTime { get; set; }
    public string Status { get; set; }  
 }

Using

using System.Net;
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;

主要程式碼

   private String GetFileContent()
        {
            string content_str = string.Empty;
            try
            {
       
                string rssContent = string.Empty;
             
                ServicePointManager.ServerCertificateValidationCallback += ValidateRemoteCertificate;
                ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls12;

                using (WebClient wc = new WebClient())
                {
                    wc.Encoding = Encoding.GetEncoding("utf-8");
                    rssContent = wc.DownloadString(----這邊放自己的url----);

                }
               
                JsonVO jsonVO = JsonConvert.DeserializeObject<JsonVO>(rssContent);
                if (jsonVO != null)
                {
                 //取回資料並做處理
                    for (var i = 0; i <= jsonVO.files.Count - 1; i++)
                    {
                        content_str += "ID = " + jsonVO.files[i].Id + ",FileName = " + jsonVO.files[i].FileName;
                    }                   
                }
            }
            catch (Exception ex)
            {
               
            }
            return content_str;
        }

private bool ValidateRemoteCertificate(object sender, X509Certificate cert, X509Chain chain, SslPolicyErrors error)
{
   if (error == System.Net.Security.SslPolicyErrors.None)
   {
      return true;
   }
   Console.WriteLine("X509Certificate [{0}] Policy Error: '{1}'", cert.Subject, error.ToString());
   return false;
}