How to save a file to a database?

ok i got it saved to the access database :-)

I defined the field as Memo and when I open the database table it looks like "System.Byte[]"... so i guess it's being saved as a byte array.

the problem is when i try to take it back out.
I do (as in the like you gave me):
Dim MyData() As Byte
MyData = myRow("file")

but it gives me the error:
Cannot convert to 'Byte()'.

and when I do:
myRow("file").GetType.Name
I get:
"String"

does this mean that it takes it out of the database as a string? Do you know what I should do?

hmm.. I haven't used a blob with Access with ADO .Net, only ADO w. VB 6.

From the looks of things, the SQL Server Image datatype is obviously smarter than the Jet Memo field, as the Memo datatype is actually really used to store text.

Looks like we need to make the following changes:

Save to the database:
myRow("imgField") = MyData.ToString()

Get from database:
      Dim MyData As String
      MyData = myRow("imgField")

      Dim fs As New FileStream _
       ("C:\winnt\Gone Fishing2.BMP", FileMode.OpenOrCreate, _
        FileAccess.Write)
      fs.Write(MyData)
      fs.Close()

I hope that works.

Dave

hmmmm all good until the line:
fs.Write(MyData)
the error is:
Value of type 'String' cannot be converted to '1-dimensional array of Byte'

So the .Write function can only except a byte array. There are to other overloaded .Write functions that take a string

errrrr

any ideas?

hmm.. How about:

        Dim f As New System.IO.StreamWriter("C:\winnt\Gone Fishing2.BMP", False)
        f.WriteLine(MyData)
        f.Close()

Dave

errrr driving me mad now.

when i save to the databse i have to do:
myRow("imgField") = MyData

cos'
myRow("imgField") = MyData.ToString() just saved the string:
"System.Byte[]"

so using:
myRow("imgField") = MyData

it gets saved as a byte array. Good.

But when I look at:
myRow("file")
it has:
?myRow("file")
"System.Byte[]" {String}
    String: "System.Byte[]"

there is actually no data there. So it failed to save the data properly to the database. I think if you save any thing to a Memo field in the database it just saves a string. I need to save it as a byte array.

I tried using the datatype OLE Object in the database but when i try saving the byte array it gives me an invalid cast exception error

Any ideas how i can save a byte array to the database? i don't think i can use the Memo field?

Hi!  bar o bach

Use OLE Object in your Access DataType because
Memo is String and in string you can not have all characters

then make your Dataset & Your DataAdaptor Again
I Put Some Code For You To Save Image To DataBase And Load Image To Memory take a look :
   'Get Image From DataBase Then Return a bitmap for u
   'Dataset1 is your DataSet
   'Table1Row is the Name Of Your DataRow
   'mRow.Image Indicate Field Image Of Your DataRow
    Public Function GetImage(ByVal mRow As DataSet1.Table1Row) As Bitmap
        Dim imgTemp As System.Drawing.Bitmap = Nothing
        Dim ms As New IO.MemoryStream(mrow.Image)  
       imgTemp = Image.FromStream(ms)
        Return imgTemp
    End Function

    'Put a Image To Your DataBase
    'oleDbDataAdapter1 is the name of Your DataAdaptor
    Public Sub PutImage(ByVal Value As System.Drawing.Bitmap)
        Dim imgfmt As System.Drawing.Imaging.ImageFormat
        Dim ms As New IO.MemoryStream
        Value.Save(ms, imgfmt.Jpeg)
        Dim MyData(ms.Length) As Byte
        MyData = ms.ToArray
        With oleDbDataAdapter1.InsertCommand
            .Connection.Open()
            .Parameters("Image").Value = MyData
            .ExecuteScalar()
            .Connection.Close()
        End With
    End Sub

any q i'm at your service ;)

Hi Barsham,

You have a bmp as the parameter to the sub that saves to the database.

For a start how can I get a bmp from my hard drive into a variable so i can pass it into the sub?

no problem you can use these lines:
'PictureBox1 -> Your PIctureBox On Screen
PictureBox1.Image=Image.FromFile("c:\temp.bmp")
putImage (PictureBox1.Image)

You Can Use Image Instead Bitmap or reverse

Cool, i'm doing pretty good now. I have the files saving to the database and then I can pick them back out and set them as the datasource of my picture box.

Nice.

The only thing now is saving them back to disk from the database. So far I got:
Dim MyData() As Byte
MyData = myRow("file")

then i do something like:
Dim f As New System.IO.StreamWriter("C:\temp.bmp", False)
f.Write(MyData)

but although the file is getting created and MyData is full of data the file that gets saves is complete empty.

Any ideas?

Thanks again for your help

any ideas Barsham or shall i close the ticket?

excellent. Worked first time....

you are a beautiful, beautiful man