c# - File Type Not Supported -

im trying send image remote server i'm taking current program. how i've done first image must saved user's workstation, i'm storing location , passing method in order pass server.

however, when run code pass image along error saying file type not supported.

here run down of code:

public static void httpuploadfile(string url, string file, string paramname, string contenttype, namevaluecollection nvc)     {         console.write(string.format("uploading {0} {1}", file, url));         string boundary = "---------------------------" + datetime.now.ticks.tostring("x");         byte[] boundarybytes = system.text.encoding.ascii.getbytes("\r\n--" + boundary + "\r\n");          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();          webresponse wresp = null;         try         {             wresp = wr.getresponse();             stream stream2 = wresp.getresponsestream();             streamreader reader2 = new streamreader(stream2);             console.write(string.format("file uploaded, server response is: {0}", reader2.readtoend()));         }         catch (exception ex)         {             console.write("error uploading file", ex);             if (wresp != null)             {                 wresp.close();                 wresp = null;             }         }                 {             wr = null;         }     } 

i'm calling method so:

  namevaluecollection nvc = new namevaluecollection();   nvc.add("id", "ttr");   nvc.add("btn-submit-photo", "upload");  httpuploadfile("http://websitelocation.com/images/uploadimage.html", sfd.tostring(),"image", "image/jpeg", nvc); 

in above method sfd relates save file dialog use save image. error this:

the given path's format not supported.

which highlighted in line:

 filestream filestream = new filestream(file, filemode.open, fileaccess.read); 

i thought above code fine send file along why i'm confused happening.

can see reason why? i've spent while looking @ , think fresh pair of eyes , brain needed.

for sake of completion string when call sfc.tostring() this:

system.windows.forms.savefiledialog: title: filename: c:\users\mycomputer\desktop\img.png

that exception message isn't complaining format of file. it's complaining format of file name. have invalid characters in path.

in code before try open file, write this:

if (file.indexofany(path.getinvalidpathchars()) >= 0) {     throw new argumentexception("file name contains invalid characters", "file"); } 

if identifies problem, best bet fix before call method. perhaps can strip offending characters or convert them underlines. without knowing more how program works, it's tough make recommendations.