How to store image in strongly typed dataset

  • Thread starter Thread starter moondaddy
  • Start date Start date
M

moondaddy

I'm caching a dataset in an asp.net session variable to hold a user's data.
one data item I need to store is an image the user uploaded. My problem is
that I don't know how to get the image into the dataset because I don't know
what datatype to set the dataset column and then set this image to. I saw
an example where someone defended a datatable in the global class and
defined the column as an object, however, when I define a strongly typed
dataset in the IDE there's no data type called object, binary, or byte().

For a start, here's how I'm getting the image data from the user
(ImageFileField is an inupt element type 'File' in the aspx):

Dim strm As Stream
strm = ImageFileField.PostedFile.InputStream
Dim lngLen As Long = strm.Length
Dim abytBuffer(CInt(lngLen - 1)) As Byte
strm.Read(abytBuffer, 0, CInt(lngLen))

So from here I have a memorystream object and a byte array both with the
image data. So now what do I do?

Thanks.
 
New problem with this. Yes I can store an image in a base64Binary column,
but when I'm stepping through the code and watching the values of variables
in the watch window, as soon as I assign the image to the dataset column,
the watch window says for the dataset: "Unable to evaluate expression".

Foe example, the text below was copied from the watch window. I put
ds.getxml as a watch:

ds.getxml "<dsCachedImages
xmlns="http://tempuri.org/dsCachedImages.xsd">
<tbImages>

<SessionID>hefuapb3rcwuzn45fzgeybml</SessionID>
<ImageId />
</tbImages>
</dsCachedImages>" String

then as soon as I assign the image, or rather the byte() variable holding
the image this is what I see in the watch window:

ds.getxml Unable to evaluate expression.

Actually the dataset is still OK as I can retrieve data from the dataset
including the image's byte array. But from this point forward I cant see
into it from the watch window. furthermore, when I get errors, along with
the error information I also record the dataset's contents into the error
log using .getxml so I can see what the data looked like at the time of the
error. now that ds.getxml can not be evaluated, I can't record its contents
into the error log. I also tried converting the byte() into a string and
saving it to a string column in the dataset and got the same result. This is
how I did that:

Dim str As String = System.Text.Encoding.Default.GetString(abytBuffer)

and this is what the string looked like in the watch window:
str "ÿØÿá#uExif String

so I appears that the string is still some of binary data which is confusing
the datase. I expected to get a much larger sting for an image 3k in size.

Is there a way to save an image to a dataset and still be able to use
ds.getxml on the dataset?
 
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