Creating Bitmap from DaoRecordSet field.
George Kostas Grous -- georgeg@btc.adaptec.com
Wednesday, March 05, 1997
Environment: MSVC 4.2b, Windows 95, Access
Greetings:
I have an access database in which 1 field is defined as an OLE Object. I
manually added bitmaps to this field using access (size 16x16 - 16 =
colors).
I created a DaoRecordSet, bound to this OLE Object column and the =
variable for
the DFX call is declared as CByteArray() (as MS suggested instead of
CLongBinary).
When the object is retrieved its size is 346 bytes (Shouln't it be 16*16 =
or 256
?) . I tried creating the bitmap by doing the following:
...
CBitmap* pBitmap =3D new CBitmap();
pBitmap->CreateBitmap(16, 16, 16, recordset->bData.GetSize(),
&recordset->bData.GetAt(0));
...
When I attempt to display the image as an icon in a tree it is garbage.
How do you extract binary data from a field in an Access database ? Is =
there a
special procedure that I am missing ? How do you add binary data to the =
db ?
I have tried a lot of methods, and nothing worked. Pointers to sample =
code or
any suggestions are greatly appreciated.
Thanks in advance.
Best regards,
George Kostas Grous
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Kefah Ibrahim -- KIbrahim_Ideal@nets.com.jo
Thursday, March 06, 1997
[Mini-digest: 2 responses]
Hi
I've answered the same questions few weeks ago, following is my answer.
Bitmap are considered Binary data, and DAO needs data to be in COleVariant to
be inserted.
Now, what you need is how to convert binary data( Bitmap) to COleVariant and
vice versa.
There is a very helpful Microsoft KBase article that has the title" How to
access Binary data using dbDoa" (PSS ID #: Q152294) under the ( C Compiler )
topics.
And because you are working on Win95 (32-bit) you need to modify the line
that use memcpy to be CopyMemory and this is the 32-bit version of memcpy !!!
Good luck,
Kefah Jizmawi
e-mail: KIbrahim_Ideal@nets.com.jo
mfc-l@netcom.com,Internet writes:
Environment: MSVC 4.2b, Windows 95, Access
Greetings:
I have an access database in which 1 field is defined as an OLE Object. I
manually added bitmaps to this field using access (size 16x16 - 16 =
colors).
I created a DaoRecordSet, bound to this OLE Object column and the =
variable for
the DFX call is declared as CByteArray() (as MS suggested instead of
CLongBinary).
When the object is retrieved its size is 346 bytes (Shouln't it be 16*16 =
or 256
?) . I tried creating the bitmap by doing the following:
...
CBitmap* pBitmap =3D new CBitmap();
pBitmap->CreateBitmap(16, 16, 16, recordset->bData.GetSize(),
&recordset->bData.GetAt(0));
...
When I attempt to display the image as an icon in a tree it is garbage.
How do you extract binary data from a field in an Access database ? Is =
there a
special procedure that I am missing ? How do you add binary data to the =
db ?
I have tried a lot of methods, and nothing worked. Pointers to sample =
code or
any suggestions are greatly appreciated.
Thanks in advance.
Best regards,
George Kostas Grous
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-----From: "Wu, Leo PL"
Hi! George ,
The size of a bitmap is the size of a header + the sizeof bits(16x16 in this
case)
the header comes first.
For the structure of header, look for BITMAPINFOHEADER in the VC document
Regards,
Leo Wu.
----------
|From: georgeg@btc.adaptec.com
|To: mfc-l@netcom.com
|Subject: Creating Bitmap from DaoRecordSet field.
|Date: Wednesday, March 05, 1997 3:52PM
|
|
|
|Environment: MSVC 4.2b, Windows 95, Access
|
|Greetings:
|
|I have an access database in which 1 field is defined as an OLE Object. I
|manually added bitmaps to this field using access (size 16x16 - 16 colors).
|
|I created a DaoRecordSet, bound to this OLE Object column and the variable
|for
|the DFX call is declared as CByteArray() (as MS suggested instead of
|CLongBinary).
|
|When the object is retrieved its size is 346 bytes (Shouln't it be 16*16 or
|256
|?) . I tried creating the bitmap by doing the following:
|
|...
|CBitmap* pBitmap = new CBitmap();
|pBitmap->CreateBitmap(16, 16, 16, recordset->bData.GetSize(),
|&recordset->bData.GetAt(0));
|...
|
|When I attempt to display the image as an icon in a tree it is garbage.
|
|How do you extract binary data from a field in an Access database ? Is
|there a
|special procedure that I am missing ? How do you add binary data to the db
|?
|I have tried a lot of methods, and nothing worked. Pointers to sample code
|or
|any suggestions are greatly appreciated.
|
|Thanks in advance.
|Best regards,
|
|George Kostas Grous
|
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|
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