using (var client = new HttpClient())
{
? ? using (var multipartFormDataContent = new MultipartFormDataContent())
? ? {
? ? ? ? var values = new[]
? ? ? ? {
? ? ? ? ? ? new KeyValuePair<string, string>("c", "3"),
? ? ? ? ? ? new KeyValuePair<string, string>("c", "2"),
? ? ? ? ? ? new KeyValuePair<string, string>("d", "2")
? ? ? ? ? ? ?//other values
? ? ? ? };
?
? ? ? ? foreach (var keyValuePair in values)
? ? ? ? {
? ? ? ? ? ? multipartFormDataContent.Add(new StringContent(keyValuePair.Value),
? ? ? ? ? ? ? ? String.Format("\"{0}\"", keyValuePair.Key));
? ? ? ? }
?
? ? ? ? multipartFormDataContent.Add(new ByteArrayContent(System.IO.File.ReadAllBytes(@"D:\test.jpg")),
? ? ? ? ? ? "\"pic\"",
? ? ? ? ? ? "\"test.jpg\"");
?
? ? ? ? var requestUri = "http://localhost:8080";
? ? ? ? var html = client.PostAsync(requestUri, multipartFormDataContent).Result.Content.ReadAsStringAsync().Result;
? ? }
}

string reqUrl = JsonrpcHttpClient.MakeRpcUrl(typeof(Wfm_SimReport).Name, "save");
using (HttpClient client = new HttpClient(new HttpClientHandler() { UseCookies = false }))//若想手動設置Cookie則必須設置UseCookies = false
{
                               
    string boundary = string.Format("----WebKitFormBoundary{0}",DateTime.Now.Ticks.ToString("x"));
    MultipartFormDataContent content = new MultipartFormDataContent(boundary);
 
    #region 設置請求參數
    content.Headers.ContentType = MediaTypeHeaderValue.Parse("multipart/form-data");
    content.Headers.Add("Cookie", TokenManager.Token);
    content.Headers.Add("client", "true");
 
    #endregion
    if (string.IsNullOrEmpty(fullPath) && !File.Exists(fullPath))
    {
        return false;
    }
 
    string fileName = Path.GetFileName(fullPath);
 
    #region Stream請求
    FileStream fStream = File.Open(fullPath, FileMode.Open, FileAccess.Read);
    content.Add(new StreamContent(fStream, (int)fStream.Length), "file", fileName);
                
    #endregion
    content.Add(new StringContent(JsonHelper.Serialize(entity)), "dtoStr");
    var result = client.PostAsync(reqUrl, content).Result;
 
    try
    {
        if (result.IsSuccessStatusCode)
        {
            string rslt = result.Content.ReadAsStringAsync().Result;
            Debug.WriteLine(rslt);
            return true;
        }
    }
    catch (Exception ex)
    {
        Debug.WriteLine(string.Format("獲取服務器返回結果錯誤：消息：{0},堆棧：{1}",ex.Message,ex.StackTrace));
    }
    finally
    {
        //關閉文件流
        fStream.Close();
        client.Dispose();
    }                
 }