6.3. Building Dynamic Forms at Runtime

Sometimes you won't know in advance how many instances of a given control might be required on a form. Let's say you're designing a form for displaying the names of all tables in a database. It's practically impossible to design a form that will accommodate every database users might throw at your application. Another typical example is a form for entering family-related data, which includes the number of children in the family and their ages. As soon as the user enters (or changes) the number of children, you should display as many TextBox controls as there are children to collect their ages.

For these situations, it is possible to design dynamic forms, which are populated at runtime. The simplest approach is to create more controls than you'll ever need and set their Visible properties to False at design time. At runtime, you can display the controls by switching their Visible properties to True. As you know already, quick-and-dirty methods are not the most efficient ones. You must still rearrange the controls on the form to make it look nice at all times. The proper method to create dynamic forms at runtime is to add controls to and remove them from your form as needed from within your code using the techniques discussed in the following sections.