How to Use ADODC in Visual Basic

The ADO (Active Data Objects) Data Control (ADODC) is a new method added in Visual Basic 6.0. It allows a programmer to put controls, such as labels, text boxes, list boxes and other display controls, on a form and connect them to the Data Control, which then connects to a database. This provides considerably more power to the developer in creating and maintaining databases. Setting up the ADODC can be complicated, but following these steps will make the process straightforward.

Difficulty: Moderately Challenging

Instructions

Things You'll Need:

• Visual Basic 6.0

1. Right click on the Visual Basic 6.0 program and choose "Run as Administrator." Start a new project by clicking on "File" and then "New Project." Select the "Data Project" template from the list.

2. 
   ADODC Control

   Double-click on the "frmDataEnv" showing in the "Data Project" list on the right. Place an ADO Data Control on the form by double-clicking on the ADODC control in the Toolbox on the left of the screen.

3. 
   Database Connection

   Set up a connection to an existing database by right-clicking on the ADODC control now on the form and choosing "ADODC Properties." On the properties page, make sure the "Use Connection String" option is selected and click "Build." Follow the steps that appear, which will lead you through selecting the type of data to use, where to find the database on your computer and whether or not to use a password.

4. 
   Connection Properties and Test

   Click on the "Test Connection" button on the "Connection" tab of the Data Link Properties when all information from step 3 is complete. If the connection fails, go back and recheck the settings chosen to connect to your database.

5. 
   Add/Delete Controls

   Place two Command buttons on the fmDataEnv by double-clicking on the "Button" control in the Toolbox and then doing this again. Change the Name of one button to "cmdAddNewRecord" and the Caption to "Add New Record." Change the Name of the other button to "cmdDeleteRecord" and the Caption to "Delete Record."

6. Double-click on the "cmdAddNewRecord" and insert this code between the beginning and end of the routine: "Adodc1.Recordset.AddNew." Do the same for the cmdDeleteRecord" button with this code: "Adodc1.Recordset.Delete." (Do not include the period at the end of this code.)

7. Write the code to take care of what should happen when the user clicks one of the choices in step 6:
   Private Sub Form_Load()
   Adodc1.Recordset.ActiveConnection.BeginTrans
   End Sub
   Private Sub Form_Unload(Cancel as Integer)
   If MsgBox("Accept record changes?", vbYesNo) = vbYes Then
   Adodc1.RecordSet.ActiveConnection.CommitTrans
   Else
   Adodc1.Recordsete.ActiveConnection.RollbackTrans
   End If
   End Sub

8. 
   Sample Database Interface

   Finish the ADODC setup by adding Labels and TextBox controls to the form to create a mechanism for a user to add or delete records. The specific controls will depend on the database needs. See the image for an example of how this will look.

Tips & Warnings

• The trickiest part about using ADODC is selecting the correct database type and using the proper connection method. This depends solely on the user's own setup. If the first choice does not work, it is just a matter of trying some other options in step 3.
• All of the code instructions must be entered exactly as shown or errors will occur. However, the actual names and captions of controls are a matter of individual choice. For example, in step 5, if you want the Caption to read "Create a New Record" you can do this. You cannot change a line like "Adodc1.RecordSet.ActiveConnection.CommitTrans" in step 7.

References

• Programming Visual Basic 6.0; Francesco Balena; 1999

Resources

• Microsoft TechNet (search for ADODC)