OLE Object

[loftty]

Hi All,

Is it possible to open a file that is stored in a Access database (OLE Object),
The file could be of any type?

Thanks

Loftty

[jmcilhinney]

No. If it's stored in a database then it isn't strictly a file. It's a bunch of bytes, and you'll get those bytes from the database as a Byte array. If you wanted to open the content as a file in its native application you'd have to save it to disc first, which you could do quite easily. That's the sort of thing the Temp folder is for. That's exactly what a browser does when you choose to open a file directly from the Web: it downloads the bytes, saves a file in the Temp folder and then opens that. A well written application will ensure that the file is deleted afterwards, if at all possible.

[loftty]

Hi,

Could you give me an example of how to do this please?

Thanks

Loftty

[jmcilhinney]

Hmmm... now I look at your first post again I could be wrong, given that your database contains OLE objects rather than actual file contents. When you retrieve a value from the database what is its type? Is it a Byte array?

[loftty]

Hi,

Yer it is a byte array

Thanks Lofty

[Wen Lie]

Hello,

Since I'll ask the same question, I think I'll join this conversation, if u don't mind loftty... ^_^
Suppose I save a picture file as an object field. How can I load the picture from that field ?

Thanks,
WJ

[loftty]

Hi Wen,

You can load the picture from a OLE field with something like this.

int PictureCol = 0; 

                string strConnFromDataBaseName = Provider + DataBaseName + ";User ID=" + Username + ";Password=" + Password + ";");       
                Connection cn = new OleDbConnection(strConnFromDataBaseName);


                OleDbCommand cmd = new OleDbCommand("SELECT [Column Name] FROM [Table Name] " +
                 "WHERE [Condition]=30", cn);

                cn.Open();
                OleDbDataReader dr = cmd.ExecuteReader();
                dr.Read();
                Byte[] b = new Byte[(dr.GetBytes(PictureCol, 0, null, 0, int.MaxValue))];
                dr.GetBytes(PictureCol, 0, b, 0, b.Length);
                dr.Close();
                cn.Close();
               
                System.Drawing.ImageConverter cvrt = new ImageConverter();
                Image img = (Image)cvrt.ConvertFrom(b);
                
                //Do what you want with the image here

Loftty

[Wen Lie]

So, after putting the OLE object into "img" variable, I can use the var ?

~ WJ ~

[loftty]

Yes you can use img.

Loftty