Introduction

In this chapter, we will discuss about the List box and Combo box controls. These controls are also called multivalue controls.

List Box Controls

Here is a list of the different types of list boxes:

• The Simple list box
• The drop-down list box
• The drop-down combo box
• The simple combo box

Simple List Boxes

The simple list box gives the users a way to select one or more items from a list of choices. You will generally not initialize the list box controls list of values from within the properties window. VB provied the means to initialize the list at runtime.

A simple list box is a list box that displays items from a list.

The programmer initializes the list, and the user cannot directly add or delete items from the simple list box.

You can use the AddItem method to add items to a list. Consider the following program segment, which adds values to the list box in the Form_Load event:

1: Private Sub Form_Load()
2:    lstNames.AddItem("Mark Waugh")
3:    lstNames.AddItem("Ricky Ponting")
4:    lstNames.AddItem("Sachin Tendulkar")
5:    lstNames.AddItem("Shane Bond")
6: End Sub

The Form_Load Event is the occurs when a form loads. A form loads:

• When the application runs, if the form is a startup form
• Via code by calling the Load statement for a form
• When any reference is made to an unloaded form's properties or controls.

This event is a good place to load initial list values.

Once you add the initial items, you can use the AddItem method to add more items to the list box.

VB adds items to the list in the same order your code adds the items, unless you change the list box's Sorter property to True. The following figure shows a simple list box

Figure 12.1

List box items have index values, and you distinguish each list box item from the others by its index. The index starts from 0 for the first item and increases without duplicates in the list. The list box's ListIndex property holds the value of the currently selected item.