我有一个包含此帖子请求的字符串：
POST /url=ws.walla.co.il/form/?itemid=2773368 HTTP/1.1
Host: localhost
Connection: keep-alive
Content-Length: 797
Cache-Control: max-age=0
Origin: https://localhost
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36
Content-Type: multipart/form-data; boundary=----WebKitFormBoundarynWW393YLgBegLQYK
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Referer: https://localhost/?url=news.walla.co.il/item/2773368
Accept-Encoding: gzip, deflate, br
Accept-Language: he-IL,he;q=0.8,en-US;q=0.6,en;q=0.4
Cookie: aeuid=247897859747575876; aeses=1; aelast=1466862543110; aestate=ab; aeb=true; _cb_ls=1; _cb=BTpqzMbWn1VDmMlcY; _chartbeat2=.1466862544444.1466862544444.1; _dy_ses_load_seq=11113%3A1469789072660; _dy_c_exps=; _dycst=dk.w.c.ws.frv2.ah.; _dy_geo=IL.AS.IL_05.IL_05_Tel%20Aviv; _dy_df_geo=Israel..Tel%20Aviv; _dy_toffset=-1; _dy_soct=12898.15511.1469789072; _dyus_8765945=34%7C360%7C0%7C3%7C8%7C0.0.1466859495876.1469789073827.2929577.0%7C210%7C31%7C6%7C116%7C4%7C0%7C0%7C0%7C0%7C0%7C0%7C4%7C0%7C0%7C0%7C0%7C7%7C4%7C7%7C0%7C0%7C0%7C0; _ga=GA1.1.1267733164.1466862541
------WebKitFormBoundarynWW393YLgBegLQYK
Content-Disposition: form-data; name="fname"
myName
------WebKitFormBoundarynWW393YLgBegLQYK
Content-Disposition: form-data; name="phone"
042895673
------WebKitFormBoundarynWW393YLgBegLQYK
Content-Disposition: form-data; name="email"
tomi@gmail.com
------WebKitFormBoundarynWW393YLgBegLQYK
Content-Disposition: form-data; name="subject"
topic
------WebKitFormBoundarynWW393YLgBegLQYK
Content-Disposition: form-data; name="content"
text
------WebKitFormBoundarynWW393YLgBegLQYK
Content-Disposition: form-data; name="multiplefile[]"; filename=""
Content-Type: application/octet-stream
------WebKitFormBoundarynWW393YLgBegLQYK
Content-Disposition: form-data; name="terms"
on
------WebKitFormBoundarynWW393YLgBegLQYK--
如何生成POST HttpWebRequest并将其发送到第一行的url？请注意帖子请求正文中的参数。
谢谢！