Use httpwebrequest post images and other files with Parameters

CodeAs follows:

Public   String Httpuploadfile ( String URL, String File, String Paramname, String Contenttype, namevaluecollection NVC)
{
String Result =   String . Empty;
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 {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 " ;
String Header =   String . Format (headertemplate, paramname, file, contenttype );
Byte [] Headerbytes = System. Text. encoding. utf8.getbytes (header );
Rs. Write (headerbytes, 0 , Headerbytes. Length );

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 );

Result = Reader2.readtoend ();
}
Catch (Exception ex)
{
If (Wresp ! =   Null )
{
Wresp. Close ();
Wresp =   Null ;
}
}
Finally
{
WR =   Null ;
}

ReturnResult;
}

Call:

// Call an instance
Namevaluecollection NVC =   New Namevaluecollection ();
NVC. Add ( " ID " , " TTR " );
NVC. Add ( " BTN-submit-photo " , " Upload " );
Httpuploadfile ( " Http://your.server.com/upload " ,
@" C: \ test \ test.jpg " , " File " , " Image/JPEG " , NVC );

 

Refer:
HTTP://Bytes

From: http://www.cnblogs.com/94cool/archive/2011/03/05/1971873.html