Re: Can images be saved to Session State and retrieved?

Vijay,

First, thanks a ton for your help. This has not been fun i know. I've
managed to figure it out thanks to you. I don't know what i was trying to do
before so your comments are all well taken, but i've just followed what
you've suggested. There's still one thing i cannot do, but it's no longer an
issue: I can now pull the image from the db, and save to the session state,
as well as convert to a bitmap. But i still cannot pull the image from the
session state object and convert to bitmap. there's clearly something that
i'm missing... here's how my code that works looks:

//Retrieve Image from database
string strCmd = String.Format("SELECT Image FROM mClient WHERE (ClientId = "
+ Session["iClientId"].ToString() + ")");
using (SqlConnection cn = utils.GetConnection())
{
cn.Open();
SqlCommand Sqlcmd = new SqlCommand(strCmd, cn);
byte[] bytImg = (byte[])Sqlcmd.ExecuteScalar();

//Creating memory stream with the raw image data
System.IO.MemoryStream MemStrm = new System.IO.MemoryStream(bytImg, true);
MemStrm.Write(bytImg, 0, bytImg.Length);

//creating bitmap with the memory stream
Bitmap bmp = new Bitmap(MemStrm);
MemStrm.Close();

myData = bytImg;

cn.Close();
}

Thanks agian!

"Vijay" wrote:

> Hi Charlie,
>
> Okay I thought I had explained that, must have missed it somewhere.
> here is the code to retrieve the image from the database.
> Assuming that the column in the database table is defined as Image [image]
> NULL in the table "Table1".
>
> ---------------------------------------------------------------------------------------------
> //Retrieve Image from database
> string strCmd = String.Format("SELECT Image FROM Table1 WHERE id = '1'",
> SqlCommand Sqlcmd = new SqlCommand(strCmd, sqlConn);
>
> byte[] bytImg = (byte[])Sqlcmd.ExecuteScalar();
>
> //Store retrieved image in session
>
> Session.Add("RawData",bytImg)
>
> //Creating memory stream with the raw image data
> System.IO.MemoryStream MemStrm = new System.IO.MemoryStream(bytImg, true);
> MemStrm .Write(bytImg, 0, bytImg.Length);
>
> //creating bitmap with the memory stream
> Bitmap bmp = new Bitmap(MemStrm);
> MemStrm.close();
>
> ------------------------------------------------------------------------------------------------
> Hope this helped.
>
> Regarding your code, I think you are missing something.
> Firstly you created a byte array "RawData" filled it with the contents of
> the dataset, where the col name was Imagesize. ->Now why is the image size a
> byte? and why is it stored in the database? (okay giving you that you need
> the image size)
> Secondly you created a memory stream from another col of the dataset which
> seems to be the Image. ->the image if stored in the database (in bytes)
> should be retrieved to the byte array and then put into a memory stream.
> Next you have used the file stream to read the "Rawdata" which now contains
> the Image Size. -> why do you need a file stream to read the byte array? also
> the byte array contains the image size!
> lastly you are storing the image size (RawData) in the session ->assuming
> you need the file size in the session, so what happened to the image in byte
> form which was to be stored in the session? and which was in the memory
> stream?
>
> I understand what you want, but your code seems wrong or probably I am
> missing something.
> anyway try the code I gave you.
> --
> --Vijay R
>
>
> "charliewest" wrote:
>
> > Vijay,
> >
> > First, i really appreciate your help sticking with this. I think i'm almost
> > there, but the examples i find (and that you provide) assume i pull the image
> > directly from the Web Form, and save the image to the Session State, and
> > then, pull the image from the session state. Where and how does the database
> > fit in?
> >
> > I've been trying to do the following with zero luck:
> >
> > byte[] RawData = new
> > byte[Convert.ToInt32(ds.Tables["Client"].Rows[0]["ImageSize"])];
> > MemoryStream stream = new MemoryStream(ds.Tables["Client"].Rows[0]["Image"],
> > FileMode.Open, FileAccess.Read);
> > Fs.Read(RawData, 0, Convert.ToInt32(Fs.Length));
> > Fs.Close();
> > Session["ImageByte"] = RawData;
> >
> > And then....
> >
> > Byte[] RawData = new byte[Convert.ToInt32(Session["ImageSize"].ToString())];
> > MemoryStream stream = new MemoryStream(RawData, true);
> > stream.Write(RawData, 0, RawData.Length);
> > Bitmap bmp = new Bitmap(stream);
> > stream.Close();
> >
> > This is really going nowhere... i really am not catching how this conversion
> > between images, bytes and bitmaps is working....
> >
> > If you could provide any insight on how the image is somehow saved to the a
> > session state var directly from the database, and how this is read from a
> > session state var... (which i think you've already provide in a former
> > response) that would be frankly amazing...
> >
> > thanks,
> >
> > "Vijay" wrote:
> >
> > > Hi Charlie,
> > >
> > > I wanted to ask,
> > > How is the bitmap stored in the database? as a Blob or in bytes?
> > > if it is stored in bytes, then I feel that Blob/Image is the better option.
> > >
> > > you can insert the byte array as I mentioned before in the Image field of
> > > the database.
> > > For retrieving and displaying the image, put the byte array into a stream
> > > and then create a bitmap file from the stream.
> > >
> > > ----------------------------------------------------------------------
> > > MemoryStream stream = new MemoryStream(RawData, true);
> > > stream.Write(RawData, 0, RawData.Length);
> > >
> > > Bitmap bmp = new Bitmap(stream);
> > > stream.close();
> > > ---------------------------------------------------------------------
> > >
> > > Hope this helped
> > >
> > > ++Vijay R
> > >
> > >
> > > "Vijay" wrote:
> > >
> > > > Hi,
> > > >
> > > > I think this should work just for converting the bitmap to a byte stream:
> > > > --------------------------------------------------------------------
> > > > FileStream Fs = new
> > > > FileStream(TextBox2.Text.Trim(),FileMode.Open,FileAccess.Read);
> > > > byte[] RawData = new byte[Fs.Length];
> > > >
> > > > Fs.Read(RawData,0,Convert.ToInt32(Fs.Length));
> > > > Fs.Close();
> > > >
> > > > Session.Add("FileData",RawData);
> > > > -------------------------------------------------------------------
> > > >
> > > > Now assuming that the file format is always bmp, we have to work on
> > > > converting it back into bmp.
> > > > will work on this :-)
> > > >
> > > > ++Vijay R
> > > >
> > > >
> > > > "charliewest" wrote:
> > > >
> > > > > Thanks Vijay,
> > > > >
> > > > > As simple as this might sound, it's taking me forever. Could you pls point
> > > > > me to some sample code?
> > > > >
> > > > > The sample code i find, requires that i know the size and file type of the
> > > > > image (bitmap) in the database, which i might not... I don't seem to find a
> > > > > sample which is as "simple" as your solution seems to imply.
> > > > >
> > > > > thanks
> > > > >
> > > > > "Vijay" wrote:
> > > > >
> > > > > > Hi,
> > > > > >
> > > > > > Why not covert the Image to Binary and then store it in session with the Img
> > > > > > format?
> > > > > > Is this a bad idea?
> > > > > >
> > > > > > ++Vijay R
> > > > > >
> > > > > >
> > > > > > "Brock Allen" wrote:
> > > > > >
> > > > > > > Why not? Check out the Bitmap class.
> > > > > > >
> > > > > > > -Brock
> > > > > > > DevelopMentor
> > > > > > > http://staff.develop.com/ballen
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > > Hello -
> > > > > > > >
> > > > > > > > I have images saved in my SQL SERVER 2000 database. Using ASP.NET (C#)
> > > > > > > > is there any way to temporarily save an image to a session object, and
> > > > > > > > after running some other operations, later retrieve the image from the
> > > > > > > > session object, convert it back to an image, and re-save it to the
> > > > > > > > database?
> > > > > > > >
> > > > > > > > Thanks?
> > > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
.