C# 上载带有进度跟踪的文件(带有参数的HttpWebRequest帖子)
我有方法C# 上载带有进度跟踪的文件(带有参数的HttpWebRequest帖子),c#,post,file-upload,httpwebrequest,C#,Post,File Upload,Httpwebrequest,我有方法HttpUploadFile上传带有一些字符串参数的图像: public static void HttpUploadFile(string url, string file, string paramName, string contentType, NameValueCollection nvc) { Console.Write(string.Format("Uploading {0} to {1}", file, url)); str
HttpUploadFile
上传带有一些字符串参数的图像:
public static void HttpUploadFile(string url, string file, string paramName, string contentType, NameValueCollection nvc)
{
Console.Write(string.Format("Uploading {0} to {1}", file, url));
string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
byte[] omg = boundarybytes;
HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(url);
wr.ContentType = "multipart/form-data; boundary=" + boundary;
wr.Method = "POST";
wr.KeepAlive = true;
wr.Credentials = System.Net.CredentialCache.DefaultCredentials;
Stream rs = wr.GetRequestStream();
string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";
foreach (string key in nvc.Keys)
{
rs.Write(boundarybytes, 0, boundarybytes.Length);
string formitem = string.Format(formdataTemplate, key, nvc[key]);
byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);
rs.Write(formitembytes, 0, formitembytes.Length);
}
rs.Write(boundarybytes, 0, boundarybytes.Length);
string headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n";
string header = string.Format(headerTemplate, paramName, file, contentType);
byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);
rs.Write(headerbytes, 0, headerbytes.Length);
FileStream fileStream = new FileStream(file, FileMode.Open, FileAccess.Read);
byte[] buffer = new byte[4096];
int bytesRead = 0;
while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
{
rs.Write(buffer, 0, bytesRead);
}
fileStream.Close();
byte[] trailer = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");
rs.Write(trailer, 0, trailer.Length);
rs.Close();
//parsing response
WebResponse wresp = null;
try
{
wresp = wr.GetResponse();
Stream stream2 = wresp.GetResponseStream();
StreamReader reader2 = new StreamReader(stream2);
String output = reader2.ReadToEnd();
}
catch (Exception ex){
Console.Write("Error uploading file" + ex.ToString());
if (wresp != null)
{
wresp.Close();
wresp = null;
}
}
finally
{
wr = null;
}
}
现在我想跟踪上传的进度。我发现了,但这个解决方案对我不起作用。您正在从文件中读取图像,并一次上载4096字节。在每4096字节之后,您可以调用一些其他函数,将进度条更新为新值 首先,您需要知道文件的总大小。无论何时上传包,您都可以计算百分比,方法是将所有发送的包相加,并将其与要发送的总字节数进行比较
正如我刚才从链接的线程中看到的,在调用GetResponse之前,HttpWebRequest没有实际发送数据可能存在问题 为了避免这种情况,您可以尝试让它立即发送数据,方法是使用一些变通方法,如设置内容长度(这意味着您需要事先知道要发送多少数据),或者可能将传输编码设置为chunked(但不知道这是否有效)。您也可以只使用原始套接字,这样您就可以完全控制。像那样发送请求需要做更多的工作,但不是很复杂 如果我稍后有时间,您决定使用原始套接字,我可以为您提供一个小示例