C# 如何在HttpClient SendRequestAsync中发送映像

我正在使用Windows.Web.Http而不是System，我正在尝试发送图像

我的示例代码：

    Dictionary<string, object> requestDictionary;
    HttpClient httpClient = new HttpClient();
    HttpRequestMessage re = new HttpRequestMessage();
    HttpResponseMessage response;
    re.Method =  HttpMethod.Post;
    re.RequestUri = url;
    string content_type = "application/json";
    string req_data = JsonConvert.SerializeObject(requestDictionary);

    re.Content = new HttpStringContent(req_data, UnicodeEncoding.Utf8, content_type);

    response = await httpClient.SendRequestAsync(re);
    response.EnsureSuccessStatusCode();

    var responseString = await response.Content.ReadAsStringAsync();

    httpClient.Dispose();
    httpClient=null;

请有人帮我实现这一点。

使用.Net 4.5（或从NuGet添加Microsoft.Net.Http包）有一种更简单的方法：

private string Upload(string actionUrl, string paramString, byte[] paramFileBytes)
{
    HttpContent stringContent = new StringContent(paramString);
    HttpContent bytesContent = new ByteArrayContent(paramFileBytes);
    using (var client = new HttpClient())
    using (var formData = new MultipartFormDataContent())
    {
        formData.Add(stringContent, "paramter");
        formData.Add(bytesContent, "image");
        var response = client.PostAsync(actionUrl, formData).Result;
        if (!response.IsSuccessStatusCode)
        {
            return null;
        }
        return response.Content.ReadAsStringAsync().Result;
    }
} 

如果您更喜欢使用流而不是字节数组，那么只需使用

newstreamcontent（）

而不是

newbytearraycontent（）

，就可以轻松做到这一点

private string Upload(string actionUrl, string paramString, byte[] paramFileBytes)
{
    HttpContent stringContent = new StringContent(paramString);
    HttpContent bytesContent = new ByteArrayContent(paramFileBytes);
    using (var client = new HttpClient())
    using (var formData = new MultipartFormDataContent())
    {
        formData.Add(stringContent, "paramter");
        formData.Add(bytesContent, "image");
        var response = client.PostAsync(actionUrl, formData).Result;
        if (!response.IsSuccessStatusCode)
        {
            return null;
        }
        return response.Content.ReadAsStringAsync().Result;
    }
}