problem with memorystream and streamwriter

[Heron]

Hi,



Could someone explain me why the following code doesn't work? The
memorystream always remains with length 0.



MemoryStream input = new MemoryStream();

StreamWriter swriter = new StreamWriter(in put);

swriter.Write(" test");

swriter.Close() ;

[Heron]

Re: problem with memorystream and streamwriter

nm, found it :)
Must user Flush() instead of Close() and keep the streamwriter open.

"Heron" <nospam@nospam. comschreef in bericht
news:uHHvkse9GH A.788@TK2MSFTNG P05.phx.gbl...

Hi,
>
>
>
Could someone explain me why the following code doesn't work? The
memorystream always remains with length 0.
>
>
>
MemoryStream input = new MemoryStream();
>
StreamWriter swriter = new StreamWriter(in put);
>
swriter.Write(" test");
>
swriter.Close() ;
>
>
>
>

[Jon Skeet [C# MVP]]

Re: problem with memorystream and streamwriter

Heron <nospam@nospam. comwrote:

Could someone explain me why the following code doesn't work? The
memorystream always remains with length 0.
>
MemoryStream input = new MemoryStream();
StreamWriter swriter = new StreamWriter(in put);
swriter.Write(" test");
swriter.Close() ;

Could you post a short but complete program which demonstrates the
problem?

See http://www.pobox.com/~skeet/csharp/complete.html for details of
what I mean by that.

Here's a program which works:

using System;
using System.IO;

class Test
{
static void Main()
{
MemoryStream input = new MemoryStream();
StreamWriter swriter = new StreamWriter(in put);
swriter.Write(" test");
swriter.Close() ;
Console.WriteLi ne (input.ToArray( ).Length);
}
}

Note that you can't access the Length property after the MemoryStream
is closed, which the StreamWriter will do when it's closed.

If you want to access the Length property while the StreamWriter is
still open, you should call Flush() first:

using System;
using System.IO;

class Test
{
static void Main()
{
MemoryStream input = new MemoryStream();
StreamWriter swriter = new StreamWriter(in put);
swriter.Write(" test");
swriter.Flush() ;
Console.WriteLi ne (input.Length);
swriter.Close() ;
}
}

--
Jon Skeet - <skeet@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

[Heron]

Re: problem with memorystream and streamwriter

Hi Jon,

Thanks for replying. Below is a complete program as requested.
My problem was in the encrypt method which is solved now but i'm still
having a problem with the decrypt method, the sreader.ReadToE nd(); method
throws me a "Padding is invalid and cannot be removed." error.

using System;
using System.IO;
using System.Security .Cryptography;
using System.Collecti ons.Generic;
using System.Text;
namespace testconsole
{
class Program
{
static void Main(string[] args)
{
byte[] key = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
13, 14, 15, 16 };
byte[] iv = new byte[] { 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,
14, 15, 16, 17 };
MyRijndael rn = new MyRijndael(key) ;
string enc = rn.Encrypt("abc defghijklmnopqr stuvwxyz", iv);
string dec = rn.Decrypt(enc, iv);
}

public class MyRijndael
{
private byte[] _key;
public MyRijndael(byte[] key)
{
this._key = key;
}
public string Encrypt(string input, byte[] iv)
{
MemoryStream output = new MemoryStream();
Rijndael rn = Rijndael.Create ();
CryptoStream scrypt = new CryptoStream(ou tput,
rn.CreateEncryp tor(this._key, iv), CryptoStreamMod e.Write);
scrypt.FlushFin alBlock();
StreamWriter swriter = new StreamWriter(sc rypt);
swriter.Write(i nput);
swriter.Flush() ;
byte[] buffer = output.ToArray( );
swriter.Close() ;
scrypt.Close();
output.Close();
return Convert.ToBase6 4String(buffer) ;
}

public string Decrypt(string input64, byte[] iv)
{
MemoryStream input = new
MemoryStream(Co nvert.FromBase6 4String(input64 ));
Rijndael rn = Rijndael.Create ();
CryptoStream scrypt = new CryptoStream(in put,
rn.CreateDecryp tor(this._key, iv), CryptoStreamMod e.Read);
StreamReader sreader = new StreamReader(sc rypt);
string res = sreader.ReadToE nd(); //<-- error
"Padding is invalid and cannot be removed."
sreader.Close() ;
scrypt.Close();
input.Close();
return res;
}
}
}
}



"Jon Skeet [C# MVP]" <skeet@pobox.co mschreef in bericht
news:MPG.1fa5d2 216862968e98d56 d@msnews.micros oft.com...

Heron <nospam@nospam. comwrote:

>Could someone explain me why the following code doesn't work? The
>memorystream always remains with length 0.
>>
>MemoryStream input = new MemoryStream();
>StreamWriter swriter = new StreamWriter(in put);
>swriter.Write( "test");
>swriter.Close( );

>
Could you post a short but complete program which demonstrates the
problem?
>
See http://www.pobox.com/~skeet/csharp/complete.html for details of
what I mean by that.
>
Here's a program which works:
>
using System;
using System.IO;
>
class Test
{
static void Main()
{
MemoryStream input = new MemoryStream();
StreamWriter swriter = new StreamWriter(in put);
swriter.Write(" test");
swriter.Close() ;
Console.WriteLi ne (input.ToArray( ).Length);
}
}
>
Note that you can't access the Length property after the MemoryStream
is closed, which the StreamWriter will do when it's closed.
>
If you want to access the Length property while the StreamWriter is
still open, you should call Flush() first:
>
using System;
using System.IO;
>
class Test
{
static void Main()
{
MemoryStream input = new MemoryStream();
StreamWriter swriter = new StreamWriter(in put);
swriter.Write(" test");
swriter.Flush() ;
Console.WriteLi ne (input.Length);
swriter.Close() ;
}
}
>
--
Jon Skeet - <skeet@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

[Jon Skeet [C# MVP]]

Re: problem with memorystream and streamwriter

Heron <nospam@nospam. comwrote:

Thanks for replying. Below is a complete program as requested.
My problem was in the encrypt method which is solved now but i'm still
having a problem with the decrypt method, the sreader.ReadToE nd(); method
throws me a "Padding is invalid and cannot be removed." error.

You're calling FlushFinalBlock before you've actually written any data.
Call it after calling Flush on the StreamWriter instead.

--
Jon Skeet - <skeet@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too