binary write problem.

[PCH]

I'm trying to pull a data file that has an image (jpeg) embedded in it.

I can locate the bytes for the image, but when I try to write it to a file,
the image ends up being corrupt!

the kb/b size is the same as the original image, but the data itself isnt.

I have the binary data in a byte array and loop through it to write it out.

When i look at the data i can see the characters are different. Like the
conversion to char isnt the same as the original, etc.

Any ideas?

heres the code...
for (int i = 0; i < bytes.Length; i++)

{

//w.Write(bytes[i]);

w.Write(System.Convert.ToChar(bytes[i]));

}

w.Close();

fs.Close();

[David Browne]

"PCH" <pc***@hotmail.com> wrote in message
news:ue**************@TK2MSFTNGP09.phx.gbl...

I'm trying to pull a data file that has an image (jpeg) embedded in it.

I can locate the bytes for the image, but when I try to write it to a file, the image ends up being corrupt!

the kb/b size is the same as the original image, but the data itself isnt.

I have the binary data in a byte array and loop through it to write it out.
When i look at the data i can see the characters are different. Like the
conversion to char isnt the same as the original, etc.

Any ideas?

heres the code...
for (int i = 0; i < bytes.Length; i++)

{

//w.Write(bytes[i]);

w.Write(System.Convert.ToChar(bytes[i]));

}

w.Close();

fs.Close();

What is w, a TextWriter?

Why on earth are you converting each byte to a char? A char is a 2-byte
unicode character.

Just write the byte array to a new IO.FileSteam object.

David

[PCH]

Why on Earth? Because I have no idea what to do hehe.
This is how I've setup the writers.
FileStream fs = new FileStream("c:\\test4.jpg", FileMode.CreateNew);

BinaryWriter w = new BinaryWriter(fs);

"David Browne" <davidbaxterbrowne no potted me**@hotmail.com> wrote in
message news:ux**************@TK2MSFTNGP12.phx.gbl...

"PCH" <pc***@hotmail.com> wrote in message
news:ue**************@TK2MSFTNGP09.phx.gbl...

I'm trying to pull a data file that has an image (jpeg) embedded in it.

I can locate the bytes for the image, but when I try to write it to a

file,

the image ends up being corrupt!

the kb/b size is the same as the original image, but the data itself isnt.
I have the binary data in a byte array and loop through it to write it

out.

When i look at the data i can see the characters are different. Like the conversion to char isnt the same as the original, etc.

Any ideas?

heres the code...
for (int i = 0; i < bytes.Length; i++)

{

//w.Write(bytes[i]);

w.Write(System.Convert.ToChar(bytes[i]));

}

w.Close();

fs.Close();

What is w, a TextWriter?

Why on earth are you converting each byte to a char? A char is a 2-byte
unicode character.

Just write the byte array to a new IO.FileSteam object.

David

[Jon Skeet [C# MVP]]

PCH <pc***@hotmail.com> wrote:

Why on Earth? Because I have no idea what to do hehe.
This is how I've setup the writers.
FileStream fs = new FileStream("c:\\test4.jpg", FileMode.CreateNew);

BinaryWriter w = new BinaryWriter(fs);

If you're just writing bytes, don't bother with a BinaryWriter at all -
just use Stream.Write(byte[], int, int).

The problem with "conversions to char" is that character data and
binary data are fundamentally different things, and shouldn't be mixed.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[PCH]

hmm it didnt like this... i looked at the image and its just #s:

StreamWriter sw = new StreamWriter("c:\\test" +
DateTime.Now.ToLongTimeString().Replace(":","_").R eplace(" ","_") + ".jpg");

sw.Write (bytes[i]);

sw.close();

"Jon Skeet [C# MVP]" <sk***@pobox.com> wrote in message
news:MP************************@msnews.microsoft.c om...

PCH <pc***@hotmail.com> wrote:

Why on Earth? Because I have no idea what to do hehe.
This is how I've setup the writers.
FileStream fs = new FileStream("c:\\test4.jpg", FileMode.CreateNew);

BinaryWriter w = new BinaryWriter(fs);

If you're just writing bytes, don't bother with a BinaryWriter at all -
just use Stream.Write(byte[], int, int).

The problem with "conversions to char" is that character data and
binary data are fundamentally different things, and shouldn't be mixed.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[Marina]

As far as I know StreamWriter is meant for text. I think a FileStream is
what you are looking for.

"PCH" <pc***@hotmail.com> wrote in message
news:uw**************@tk2msftngp13.phx.gbl...

hmm it didnt like this... i looked at the image and its just #s:

StreamWriter sw = new StreamWriter("c:\\test" +
DateTime.Now.ToLongTimeString().Replace(":","_").R eplace(" ","_") + ".jpg");
sw.Write (bytes[i]);

sw.close();

"Jon Skeet [C# MVP]" <sk***@pobox.com> wrote in message
news:MP************************@msnews.microsoft.c om...

PCH <pc***@hotmail.com> wrote:

Why on Earth? Because I have no idea what to do hehe.
This is how I've setup the writers.
FileStream fs = new FileStream("c:\\test4.jpg", FileMode.CreateNew);

BinaryWriter w = new BinaryWriter(fs);

If you're just writing bytes, don't bother with a BinaryWriter at all -
just use Stream.Write(byte[], int, int).

The problem with "conversions to char" is that character data and
binary data are fundamentally different things, and shouldn't be mixed.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[Jon Skeet [C# MVP]]

PCH <pc***@hotmail.com> wrote:

hmm it didnt like this... i looked at the image and its just #s:

StreamWriter sw = new StreamWriter("c:\\test" +
DateTime.Now.ToLongTimeString().Replace(":","_").R eplace(" ","_") + ".jpg");
No, StreamWriter is *not* what you want - again, that's talking about
characters.
sw.Write (bytes[i]);

That would have written a single byte - again, not what you want.

Just create a FileStream, and call Write on it.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[PCH]

I think i got it!

fs.Write((byte[]) bytes,ipos,bytes.Length -ipos);

image is saved correctly.

Thanks for the help!

"Jon Skeet [C# MVP]" <sk***@pobox.com> wrote in message
news:MP***********************@msnews.microsoft.co m...

PCH <pc***@hotmail.com> wrote:

hmm it didnt like this... i looked at the image and its just #s:

StreamWriter sw = new StreamWriter("c:\\test" +
DateTime.Now.ToLongTimeString().Replace(":","_").R eplace(" ","_") +

".jpg");
No, StreamWriter is *not* what you want - again, that's talking about
characters.

sw.Write (bytes[i]);

That would have written a single byte - again, not what you want.

Just create a FileStream, and call Write on it.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too