Computer Programming Concepts and Visual Basic David I. Schneider

9. Click on the down arrow to the right of the Settings box and select datCities.
10. Select the DataField property and click on the down arrow at the right of the
Settings box.
You will see the names of the different fields in the table.
11. Select the field city.
The text box now is said to be bound to the data control. It can now display data
from the city field of the Cities table.
12. Place another text box, txtPop1995, on the form.
13. Select txtPop1995’s DataSource property.
14. Click on the down arrow to the right of the Settings box and select datCities.
15. Select the DataField property, click on the down arrow at the right of the Settings
box, and select pop1995.
16. Run the program.
The form will appear as in Figure 11-1. The arrows on the data control, called
navigation arrows, look and act like VCR buttons. The arrows have been identified
by the tasks they perform.
17. Click on the various navigation arrows on the data control to see the different
cities and their populations in the Cities table displayed in the text boxes.
18. Change the name of a city or change its population and then move to another
record.
If you look back through the records, you will see that the data have been permanently
changed.
FIGURE 11-1 A Data Control with Two Text Boxes Bound to It
■ USING CODE WITH A DATA CONTROL
Only one record can be accessed at a time; this record is called the current record. In this walkthrough,
the text boxes bound to the data control showed the contents of the city and pop1995
fields of the current record. The user clicked on the navigation arrows of the data control to
select a new current record.
Code can be used to designate another record as the current record. The methods
MoveNext, MovePrevious, MoveLast, and MoveFirst select a new current record as suggested
by their names. For instance, the statement
Data1.Recordset.MoveLast
specifies the last record of the table to be the current record. (The word Recordset is inserted
in most data-control statements that manipulate records for reasons that needn’t concern us
now.)
The entry of the field fieldName of the current record is
Data1.Recordset.Fields(“fieldName”).Value
For instance, with the status as in Figure 11-1, the statement
strVar = datCities.Recordset.Fields(“city”).Value
An Introduction to Databases 325