Using ADO Control

Now you will learn how to create ADO-based applications. We will use the sample BIBLIO.MDB database that comes with Visual Basic. The source code needed for this example is stored in the "Source Code\Chapter23\ADO Control " directory.

First, you must connect the control to the data the control will access. You can connect a data source to the ADO control in two ways:

• Set the ConnectionString property.
• Use code to connect the control to the data.

Create a new application. Press Ctrl+T to open the Components dialog box and select Microsoft Active Data Control 6.0 to place the ADO control on the tollbox. Add the control to the form. Now click the ConnectionString property, the dialog box shown in the following appears:

For this simple example, the first two options, a Data Link File option and an ODBC file option, are not needed. Click the third option to specify a connection string. Follow the following steps to build the connection string:

• Click the build button to display the Data Link Properties dialog box.
• Double click the first option labeled Microsoft Jet 3.51 OLE DB provider.
• Click the ellipses button to the right of the first text box and locate BIBLIO.MDB database.
• Click the OK button to return to the first Property Pages dialog box page; then click OK to close the dialog box and return to your form.

Now Double click the RecordSource property and select the following:

• Command Type: 2-adCmdtable
• Table Name: Authors
  

Now add label controls to the form and bind them. You learned to do this kind of binding with the simple Data control. When you run the application, you will see the following:

Today's lesson explained database access with Visual Basic. The simplest way to access a database is to add the data control to your form. Methods can be used to extend the functionality of the data control. The ADO interface requires extensive programming, but you get much more control and flexibility when accessing your database.