Como pasar un campo imagen de SQL Server a un PictureBox
Iván Pascual
Tengo un 'pequeño' problemilla que consiste en usar una tabla de SQL
SERVER con un campo que es del tipo 'imagen' (el quivalente a OLE en
Access). Lo único que necesito es pasar dicha imagen a un PictureBox. He
visto métodos (Appendchunk & Getchunk) que crean un fichero en disco para
hacer el proceso, pero creo que se puede ahorrar ese paso. También he visto
el uso del objeto ADO.Stream para hacer lo mismo, pero no he podido hacerlo
funcionar.
Si alquien sabe como solucionar esto sin crear el archivo en disco, le ruego
que responda.
Gracias a todos.
Norman A. Armas
ahora bien como hacerlo sin grabar en disco sinceramente no se.....
HOWTO: Access and Modify SQL Server BLOB Data by Using the ADO Stream
Object
Q258038
The information in this article applies to:
ActiveX Data Objects (ADO), version 2.5
Microsoft Visual Basic Professional Edition for Windows, version 6.0
Microsoft Visual Basic Enterprise Edition for Windows, version 6.0
Microsoft OLE DB Provider for SQL Server, version 7.0
SUMMARY
The Stream object introduced in ActiveX Data Objects (ADO) 2.5 can be used
to greatly simplify the code that needs to be written to access and modify
Binary Large Object (BLOB) data in a SQL Server Database. The previous
versions of ADO [ 2.0, 2.1, and 2.1 SP2 ] required careful usage of the
GetChunk and AppendChunk methods of the Field Object to read and write BLOB
data in fixed-size chunks from and to a BLOB column. An alternative to this
method now exists with the advent of ADO 2.5. This article includes code
samples that demonstrate how the Stream object can be used to program the
following common tasks:
Save the data stored in a SQL Server Image column to a file on the hard
disk.
Move the contents of a .gif file to an Image column in a SQL Server table.
MORE INFORMATION
The following code samples are based on the data stored in the pub_info
table in the SQL Server 7.0 pubs sample database. You need to modify the ADO
connection string to point to your SQL Server installation.
Example 1 : Saving the Data in a SQL Server Image Column to a File on the
Hard Disk
The code in this example opens a recordset on the pub_info table in the pubs
database and saves the binary image data stored in the logo column of the
first record to a file on the hard disk, as follows:
Open a new Standard EXE Visual Basic project.
On the Project menu, click to select References, and then set a reference to
the Microsoft ActiveX Data Objects 2.5 Object Library.
Place a CommandButton control on Form1.
Make the following declarations in the form's General declarations section:
Dim cn As ADODB.Connection
Dim rs As ADODB.Recordset
Dim mstream As ADODB.Stream
Cut and paste the following code into the Click event of the CommandButton
that you added to the form:
Set cn = New ADODB.Connection
cn.Open "Provider=SQLOLEDB;data Source=<name of your SQL Server>;
Initial Catalog=pubs;User Id=<Your Userid>;Password=<Your Password>"
Set rs = New ADODB.Recordset
rs.Open "Select * from pub_info", cn, adOpenKeyset, adLockOptimistic
Set mstream = New ADODB.Stream
mstream.Type = adTypeBinary
mstream.Open
mstream.Write rs.Fields("logo").Value
mstream.SaveToFile "c:\publogo.gif", adSaveCreateOverWrite
rs.Close
cn.Close
Save and run the Visual Basic project.
Click the CommandButton to save the binary data in the logo column of the
first record to the file c:\publogo.gid. Look for this file in Windows
Explorer and open it to view the saved image.
The code in this example declares an ADODB Stream object and sets its Type
property to adTypeBinary to reflect that this object will be used to work
with Binary data. Following this, the binary data stored in the logo column
of the first record in the pub_info table is written out to the Stream
object by calling its Write method. The Stream object now contains the
binary data that is saved to the file by calling its SaveToFile method and
passing in the path to the file. The adSaveCreateOverWrite constant passed
in as the second parameter causes the SaveToFile method to overwrite the
specified file if it already exists.
Example 2 : Transfer the Image Stored in a .gif File to an Image Column in a
SQL Server Table
The code in this example saves an image stored in a .gif file to the logo
column in the first record of the pub_info table by overwriting its current
contents, as follows:
Open a new Standard EXE Visual Basic project.
On the Project menu, click to select References, and then set a reference to
the Microsoft ActiveX Data Objects 2.5 Object Library.
Place a CommandButton on Form1.
Make the following declarations in the form's General declarations section:
Dim cn As ADODB.Connection
Dim rs As ADODB.Recordset
Dim mstream As ADODB.Stream
Cut and paste the following code in the Click event of the CommandButton
that you added to the form:
Set cn = New ADODB.Connection
cn.Open "Provider=SQLOLEDB;data Source=<name of your SQL Server>;
Initial Catalog=pubs;User Id=<Your Userid>;Password=<Your Password>"
Set rs = New ADODB.Recordset
rs.Open "Select * from pub_info", cn, adOpenKeyset, adLockOptimistic
Set mstream = New ADODB.Stream
mstream.Type = adTypeBinary
mstream.Open
mstream.LoadFromFile "<path to .gif file>"
rs.Fields("logo").Value = mstream.Read
rs.Update
rs.Close
cn.Close
Save and run the Visual Basic project.
Click on the CommandButton to run the code to stream the contents of the
.gif file to the ADO Stream object, and save the data in the Stream to the
logo column in the first record of the recordset.
Verify that the image in the logo column has been modified by using the code
in Example 1.
Additional query words:
Keywords : kbVBp600 kbSQLServ700 kbGrpDSVBDB kbDSupport kbMDAC250 kbADO250
Issue type : kbhowto
Technology : kbVBSearch kbSQLServSearch kbAudDeveloper kbADOsearch kbADO250
kbZNotKeyword6 kbZNotKeyword2 kbVB600Search kbVBA600 kbVB600 kbOLEDBSearch
kbOLEDBProvSQLServ700
Last Reviewed: May 12, 2001
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============
Saludos
Norman
"Iván Pascual" <iv...@hermet10.com> wrote in message
news:9u64hm$seu$1...@talia.mad.ttd.net...