Asp.net C#相当于此curl Post请求

$curl

-X柱

-H'授权：持有您的\u访问\u令牌'

-F'收件人[0][全名]=John'-F'收件人[0][电子邮件]=John。doe@gmail.com"

-F'文件[0]=@NDA.pdf'

-F'交付类型=url'

我做过这个“翻译成asp.net”我是新来的，我正在学习asp.net MVC

但我一直在犯错误

 public static string SendSignatureRequest(string apiKey, string name, string email, string file)
{
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create("https://api.sandbox.signaturit.com/v3/signatures.json");
    request.Method = "POST";

    var postData = "&signers[0][name]=" + HttpUtility.UrlEncode(name);
        postData += "&signers[0][email_address]=" + HttpUtility.UrlEncode(email);
        postData += "&file_url[0]=" + HttpUtility.UrlEncode(file);// OR -- postData += "&file[0]=" + HttpUtility.UrlEncode(file);


    var data = Encoding.ASCII.GetBytes(postData);

    request.ContentType = "application/x-www-form-urlencoded";
    request.ContentLength = data.Length;

    string authorization = apiKey;
    request.Headers.Add("Authorization", "Bearer " + authorization);

    using (var stream = request.GetRequestStream())
    {
        stream.Write(data, 0, data.Length);
    }

    HttpWebResponse response = (HttpWebResponse)request.GetResponse();
    return new StreamReader(response.GetResponseStream()).ReadToEnd();
}