Visual Basic Q&A

Symptoms
The Microsoft Data Object Libraries may be referenced in your Visual Basic project. When the Package and Deployment Wizard (PDW) is used to build the installation, the PDW scans the project files and determines which dependency files need to be distributed.
This article provides the general information you need to distribute any of the following Data Object Libraries with your Visual Basic project: Microsoft Data Access Objects (DAO) 3.51 Object LibraryMicrosoft Data Access Objects (DAO) 3.6 Object LibraryMicrosoft Remote Data Object (RDO) 2.0Microsoft ActiveX Data Objects (ADO) 2.0, 2.1, 2.5, or 2.6 Library
Resolution
The files are listed in the Setup’s file that is created by the PDW for distribution.
For additional information on how each section in the Setup.lst file is used, click the following article number to view the article in the Microsoft Knowledge Base:
189743?(http://support.microsoft.com/kb/189743/) Description of Setup.lst sections The following sections describe points to be aware of when you distribute any of the Data Object Libraries.
Microsoft Data Access Objects (DAO) 3.51 Object LibraryIntrinsic data control incompatibility with Microsoft Access 2000 (Jet 4.0) If you use the intrinsic data control in your project and you attempt to connect to a Microsoft Access 2000 database, you may receive the following error message:

Unrecognized Database Format This error message occurs because the DAO generic data control is based on Jet 3.51 and does not recognize Jet 4.0 database formats. Access 2000 is a Jet 4.0 format database. Prior to Microsoft Visual Studio 6.0 Service Pack 4 (SP4), the workaround for this problem was to open a recordset with DAO code, and then assign it to the recordset property of a data control. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
238401?(http://support.microsoft.com/kb/238401/) PRB: Unrecognized database format error message when upgrading to Access 2000 This problem does not exist with the data control that ships with Microsoft Visual Studio 6.0 Service Pack 6.
Visual Studio 6.0 Service Pack 6 can be obtained at the Visual Studio 6.0 Service Pack Web site:
http://msdn2.microsoft.com/en-us/vstudio/aa718364.aspx(http://msdn2.microsoft.com/en-us/vstudio/aa718364.aspx)Jet 3.51 OLE DB Provider is not included in MDAC 2.1 or later The Jet OLE DB Provider requires the version number of the provider in order to connect to an Access database. If your application specifies Version 3.51 of the Jet OLE DB provider in a connection string or a UDL, and you install ADO by redistributing MDAC 2.1, you are likely to receive the following error message:

3706: ADO could not find the specified provider This error message occurs because MDAC 2.0 installs version 3.51 of the Jet OLE DB provider while MDAC 2.1 installs version 4.0 of the Jet OLE DB Provider, but does not install version 3.51. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
197902?(http://support.microsoft.com/kb/197902/) PRB: Jet 3.51 OLE DB Provider is not installed with MDAC 2.1 or later
Microsoft Data Access Objects (DAO) 3.6 Object Library DAO version 3.6 is required for applications that use DAO to read and write to Access 2000 databases. If Access 2000 (or DAO 3.6) is already installed on the destination computer, then no additional steps are required. If it is not, it is necessary to distribute DAO 3.6. However, there is currently no redistributable for DAO 3.6. In order to redistribute DAO 3.6, it is necessary to install DCOM, redistribute MDAC 2.1(GA) or later, and ensure that the DAO DLL is also distributed and registered on the destination computer.
For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
233002?(http://support.microsoft.com/kb/233002/) How to redistribute DAO 3.6
Microsoft Remote Data Object (RDO) 2.0 In order for RDO to be properly distributed and installed, ODBC must already be installed on the destination computer. ODBC can be installed through the odbcst32.exe file, which is located in the ODBC Folder under the SQL/i386 directory on Visual Basic 6.0 Disk 2. ODBC can also be installed by including the MDAC redistributable in the distribution that is outlined in the “References” section covering distributing ADO/MDAC. To determine all of the files needed to distribute for RDO to work successfully on a computer that does not have Visual Basic installed, you can generate a dependency (.dep) file with the Package and Deployment Wizard. To generate a dependency file that shows the files needed for RDO when running the PDW, complete the following steps: Create a Standard EXE project in Visual Basic. Form1 is created by default.Add a reference to Microsoft Remote Data Object 2.0.Save this project and run the Package and Deployment Wizard on it.Select the Package option.On the Package Type, choose Dependency File, and then proceed through the wizard to completion. When you are finished, you have a file with a .dep extension that can be opened with Microsoft Notepad. MSRDO20.dll and its dependencies are shown in this file.
You want to ensure that these files are included with the distribution. If these files are not listed on the Included Files dialog box when you run the Package and Deployment Wizard, include them by clicking Add in the dialog box.
Microsoft ActiveX Data Objects (ADO) 2.0, 2.1 or 2.5 Library The PDW does not distribute mdac_typ unless there is a specific reference to an ADO Library (any version) in the project.
You can also add mdac_typ.exe manually by clicking Add in the Included Files dialog box when you run the Package and Deployment Wizard. The wizard uses the MDAC_Typ.exe file in the …\Wizards\PDWizard\Redist folder. Obtain the MDAC Components at the following Microsoft Web site:
http://msdn2.microsoft.com/en-us/data/aa937695.aspx(http://msdn2.microsoft.com/en-us/data/aa937695.aspx) For additional information how the PDW distributes MDAC, click the following article number to view the article in the Microsoft Knowledge Base:
217754?(http://support.microsoft.com/kb/217754/) How to control which MDAC version the Package and Deployment Wizard (PDW) distributes The installation of Microsoft Data Access Components (MDAC) requires that DCOM be already installed on the destination computer: For Windows 95 computers, install DCOM95.For Windows 98 computers, install DCOM98.Download the latest version of DCOM from the following Microsoft Web page:
http://www.microsoft.com/downloads/details.aspx?familyid=08B1AC1B-7A11-43E8-B59D-0867F9BDDA66&displaylang=en(http://www.microsoft.com/downloads/details.aspx?familyid=08B1AC1B-7A11-43E8-B59D-0867F9BDDA66&displaylang=en) If DCOM is not already installed on the destination computer, you may receive one of the following error messages:

Unable to load file ‘msdadc.dll’ to register it
-or-

DLL registration failed For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
191704?(http://support.microsoft.com/kb/191704/) PRB: Unable to load file to register it during setup

Symptoms
Microsoft Visual Basic ships with an add-in utility known as the Visual Data Manager (VISDATA) for which source code is also provided in the form of a sample project named Visdata.vbp. Visdata.vbp is installed with other Visual Basic samples as part of the MSDN Library installation.
This article describes how to modify the source code for the Visual Data Manager add-in in order to use the add-in with Microsoft Access 2000 format database files.

Resolution
Adapting VISDATA to work with Microsoft Access 2000 format databases requires changing only one project reference, adding one menu item, and adding one line of code to process the new menu item.
Update the DAO Reference from DAO 3.51 to DAO 3.60. (This step alone is sufficient to allow you to open and work with Access 2000 files.)Open Visdata.vbp in the Visual Basic design environment.On the Project menu, open the list of References.Deselect the existing reference to Microsoft Data Access Objects 3.51, and then locate and select Microsoft Data Access Objects 3.60. If you are using Visual Basic 6.0, be sure to move the DAO 3.6 reference above the ADO library reference in the list.Add a new menu item and code to allow creating a new Access 2000 database.Open the main form, frmMDI, in the design environment.From the Tools menu, open the Menu Editor.In the Menu Editor window, scroll down in the existing menu items to File / New / Microsoft Access.In order to insert the new menu item after the existing entry for Access Version 7.0 MDB files, select the following entry: dBase. Click the Insert button, and then click the RIGHT ARROW button to make the new, blank entry a subitem under the Microsoft Access heading. Enter Access 2000 as the Caption and mnuDBNMDB2K as the Name. Close the Menu Editor by clicking OK.Open the frmMDI code module and select the mnuDBNMDB2K_Click event procedure in the drop-down list. Enter the following line of code:

NewMDB dbVersion40In Visual Basic 6.0 only, update ADO connection strings to support Access 2000.VisData uses both DAO and ADO. Use the Search function on the Visual Basic Edit menu to locate all references in the project to the Microsoft Jet OLE DB Provider version 3.51 and update 3.51 to 4.0.In Visual Basic 6.0 only, add code that will enable the Grid toolbar button, which displays a table of records in a DBGrid control rather than one record per form.Open the module modVisData and find the OpenTable procedure.After the lines:

If gsDataType = gsMSACCESS Then.ConnectionString = “PROVIDER=Microsoft.Jet.OLEDB.4.0;Data Source=” & gsDBName insert the additional line:

.CursorLocation = adUseClient Then open frmDataGrid and find the Form_Load event procedure.After the line:

Set datDataCtl.Recordset = mrsFormRecordset insert the additional lines:

datDataCtl.RefreshSet grdDataGrid.DataSource = datDataCtlgrdDataGrid.Refresh If you were to omit this step, you might see an empty grid; or the grid may display with the very first cell empty.Recompile the VISDATA project and copy the compiled executable to the Visual Basic directory (which is \Program Files\Microsoft Visual Studio\Vb98 by default in Visual Basic 6.0).

Symptoms
When you attempt to connect to a Microsoft Access 2000 database by using either the standard Data control or the Data Form Wizard, you see the following error message where ‘…\databasename.mdb’ is the absolute filename of the Access 2000 database:

Unrecognized database format ‘…\databasename.mdb’”
Resolution
The standard Data control uses Data Access Object (DAO) 3.51 to connect to Access databases by using the Jet 3.51 engine.
The Data Form Wizard uses the Jet 3.51 OLE DB Provider to connect to Access databases by using the Jet 3.51 engine.
The Jet 3.51 engine can connect to Access database versions prior to Access 2000, but cannot connect to Access 2000 databases.

Symptoms
When you try to create a Microsoft Access 97 table from a Visual Basic project, you may receive the following error message:

-2147217900(80040e14):
[Microsoft][ODBC Microsoft Access Driver] Field ‘(The second column name)’ already exists in table ‘HWC’The problem does not occur with a Microsoft Access 2000 database.
This problem arises when you attempt to create a table with two columns that contain double-byte character sets whose fields are the same length.This problem only occurs with the Jet 4.0 OLE-DB provider and the Access ODBC driver.
Resolution
Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article. This bug was corrected in the latest service pack for Visual Studio 6.0.
For additional information about Visual Studio service packs, click the following article numbers to view the articles in the Microsoft Knowledge Base:
194022?(http://support.microsoft.com/kb/194022/EN-US/) INFO: Visual Studio 6.0 Service Packs, What, Where, Why
194295?(http://support.microsoft.com/kb/194295/EN-US/) HOWTO: Tell That a Visual Studio Service Pack Is InstalledTo download the latest Visual Studio service pack, visit the following Microsoft Web site:
http://msdn2.microsoft.com/en-us/vstudio/Aa718353.aspx(http://msdn2.microsoft.com/en-us/vstudio/Aa718353.aspx)In addition, the Jet 3.51 OLEDB provider does not exhibit this behavior.