List Boxes Checked List Boxes Combo Boxes Picture Boxes Immediate Solutions: Using the ListBox Class Adding Items to a List Box Referring to Items in a List Box by Index Responding to List Box Events Removing Items from a List Box Sorting a List Box Determining How Many Items Are in a List Box Determining Which List Box Items Are Selected Making List Boxes Scroll Horizontally (Multicolumn List Boxes) Creating Multiselect List Boxes Clearing a List Box Using the CheckedListBox Class Adding Items to Checked List Boxes Determining What Items Are Checked in Checked List Boxes Checking or Unchecking Items in Checked List Boxes from Code Handling Item Check Events in Checked List Boxes Using the ComboBox Class Creating Simple Combo Boxes, Drop-down Combo Boxes, and Drop-down List Combo Boxes Adding Items to a Combo Box Responding to Combo Box Selections Removing Items from a Combo Box Getting the Current Selection in a Combo Box Sorting a Combo Box Clearing a Combo Box Getting the Number of Items in a Combo Box Storing Objects in a List Box or Combo Box Using the PictureBox Class Setting or Getting the Image in a Picture Box Adjusting Picture Box Size to Contents Handling Picture Box Events (and Creating Image Maps)
In this chapter, we're going to take a look at four popular Visual Basic controls: list boxes, checked list boxes, combo boxes, and picture boxes. These controls are part of the core arsenal of every Visual Basic programmer.
List boxes, of course, do just what their name implies: display a list of items. The user can make a selection from that list, and we can handle such selections with event handlers. Because list boxes can use scroll bars if a list gets too long, these controls are very useful to present long lists of items in a way that doesn't take up too much space.
Checked list boxes are derived from list boxes, and also support a checkbox for each item in a list. In VB6 and before, you could add checkboxes to ordinary list boxes, but in VB .NET, checked list boxes are separate controls. These controls are useful when you've got a long list of checkable items and want to scroll that list. We'll see how to handle checkbox events in this control.
Combo boxes are list boxes combined with text boxes. With combo boxes, you can give the user the option of selecting from a list (usually a drop-down list activated when the user clicks the downward pointing arrow at right in a combo box) or typing their selection directly into the text box part of the combo box.
Picture boxes display images, as their name implies. In VB6 and before, picture boxes were powerhouses, not only displaying images, but also letting you edit them as well as reading images from disk and saving them too. And picture boxes were container controls, letting you insert other controls into them. (In fact, in Visual Basic's early days, you used to create toolbars with picture boxes which you filled with buttons.) All that's changed now, unfortunately, and picture boxes have been made much more like VB6's image controls, which only displayed images (image controls do not exist in VB .NET).
I'll take a look at all these controls in some detail here in the In Depth section.