c# - 将文件和字符串上传到 http 然后获取响应

Question

基本上我有一个服务器可以让你上传文件，但它需要登录，所以当我从客户端上传时，我不仅需要发送要上传的文件，还需要将用户名和密码作为字符串发送，然后读取来自服务器。我已尽力而为，但出现错误“您必须在调用 [Begin]GetResponse 之前将 ContentLength 字节写入请求流。”

我上传图片的代码：

string ImgFile = Path.GetTempFileName();
img.Save(ImgFile);

byte[] LoginBytes = ASCIIEncoding.ASCII.GetBytes("username=" + Username + "&password=" + Password);
byte[] ImageBytes = File.ReadAllBytes(ImgFile);
int ByteLen = LoginBytes.Length + ImageBytes.Length;

WebRequest ReqResponse = WebRequest.Create(url);
ReqResponse.Credentials = CredentialCache.DefaultCredentials;
ReqResponse.Proxy = WebRequest.DefaultWebProxy;
ReqResponse.Proxy.Credentials = CredentialCache.DefaultCredentials;
ReqResponse.Method = "POST";
ReqResponse.ContentType = "application/x-www-form-urlencoded";
ReqResponse.ContentLength = ByteLen;

ReqResponse.GetRequestStream().Write(LoginBytes, 0, LoginBytes.Length);
ReqResponse.GetRequestStream().Write(ImageBytes, 0, ImageBytes.Length);

string response = (new StreamReader(ReqResponse.GetResponse().GetResponseStream()).ReadToEnd());
MessageBox.Show(response);

Answer 1

maybe it doesn't like 2 posts? could just concat them and send them at once.

void Main()
{
byte[] login = BitConverter.GetBytes("loginstring");
byte[] img = BitConverter.GetBytes("fakeimagedataherereplacewithrealbytes");
byte[] tosend = login.Concat(img).ToArray();
using(WebRequest wr = WebRequest.Create("someurl"))
{
    using (Stream rs = wr.GetRequestStream())
    {
        rs.Write(LoginBytes, 0, LoginBytes.Length);
        //...whatever
    }

}

}