Converting byte[] to .Net image

Hello there,

I try to handle bitmap images stored in an Image column in Sql Server. The
following code is ok when the image is of type Bitmap (*.bmp):

private ImageSource ConvertByteArrayToImageSource(byte[] bdIconeArray) {
ImageSource imgSource = null;
MemoryStream strm = new MemoryStream();
BitmapImage bitmap = new BitmapImage();

// Well-known work-around to make Northwind images work
int offset = 78;
strm.Write( bdIconeArray, offset, bdIconeArray.Length - offset );

// Read the image into the bitmap object
bitmap.BeginInit();
bitmap.StreamSource = strm;
bitmap.EndInit();

imgSource = bitmap;
return imgSource;
}

However, it doesn't work with png, jpg or Tiff image stored in the database.
Must the Offset be different ?

Oriane

Re: Converting byte[] to .Net image

You need to use a Decoder to translate the format. There is a
JpegBitmapDecoder class, a TiffBitmapDecoder class, and a PngBitmapDecoder
class. Here's a link to the JpegBitmapDecoder class, from which you can get
the documentation and sample code, as well as navigate to the similar
documentation for the other decoder classes:

http://msdn2.microsoft.com/en-us/library/system.windows.medi a.imaging.jpegbitmapdecoder.aspx

--
HTH,

Kevin Spencer
Chicken Salad Surgeon
Microsoft MVP

"Oriane" wrote in message
news:26CF3E53-C950-43EE-8D8B-39121D950498@microsoft.com...
> Hello there,
>
> I try to handle bitmap images stored in an Image column in Sql Server. The
> following code is ok when the image is of type Bitmap (*.bmp):
>
> private ImageSource ConvertByteArrayToImageSource(byte[] bdIconeArray) {
> ImageSource imgSource = null;
> MemoryStream strm = new MemoryStream();
> BitmapImage bitmap = new BitmapImage();
>
> // Well-known work-around to make Northwind images work
> int offset = 78;
> strm.Write( bdIconeArray, offset, bdIconeArray.Length - offset );
>
> // Read the image into the bitmap object
> bitmap.BeginInit();
> bitmap.StreamSource = strm;
> bitmap.EndInit();
>
> imgSource = bitmap;
> return imgSource;
> }
>
> However, it doesn't work with png, jpg or Tiff image stored in the
> database. Must the Offset be different ?
>
> Oriane

Re: Converting byte[] to .Net image

Hi Kevin,

"Kevin Spencer" a écrit dans le message de
news:O83RnpMOIHA.4272@TK2MSFTNGP06.phx.gbl...
> You need to use a Decoder to translate the format. There is a
> JpegBitmapDecoder class, a TiffBitmapDecoder class, and a PngBitmapDecoder
> class. Here's a link to the JpegBitmapDecoder class, from which you can
> get the documentation and sample code, as well as navigate to the similar
> documentation for the other decoder classes:
>
> http://msdn2.microsoft.com/en-us/library/system.windows.medi a.imaging.jpegbitmapdecoder.aspx
I've tried this code:
____________________________________________________________ _________________
Byte [] dbIconeArray = ... // Get from Sql Server
MemoryStream strm = new MemoryStream();

// Well-known work-around to make Northwind images work
int offset = 0;
strm.Write( bdIconeArray, offset, bdIconeArray.Length - offset );
BmpBitmapDecoder decoder = new BmpBitmapDecoder(strm,
BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default);
BitmapSource bitmapSource = decoder.Frames[0];
imgSource = bitmapSource;
____________________________________________________________ __________________________

and I get an exception.

Now if I set (like before) thge variable offset to 78, it works !!!

The same code with PngBitmapDecoder fails with offset = 0 or offset=78.

Thanks a lot !