11.20. Prepopulating a Form

Problem

You want to programmatically fill in a form with defaults or a user’s previous selections.

Solution

Use the methods and properties that allow you to set the values of each form element.

Discussion

Each type of form element has different ways of selecting the element or modifying its value. For example, you can set a text field’s contents using the text property:

myTextField_txt.text = value;

You can set combo boxes and single-select list boxes using the setSelectedIndex( ) method. This method requires you to know the index of the item you wish to select programmatically (and not just its label or data value).

// Selects the third item from the menu
myComboBox_cb.setSelectedIndex(2);

You can programmatically select multiple items from a multiple-selection list box using the setSelectedIndices( ) method, which accepts an array of indexes to select:

// Selects the first three menu items from a multiple-selection list box
myListBox_lb.setSelectedIndices([0, 1, 2]);

To set a combo box or list box by its label or data property (rather than by its index), you can create a custom setSelectedItem( ) method for FSelectableListClass (the superclass of both combo boxes and list boxes). The method should accept a single parameter, which is the data value for the desired menu item. If the data properties of the menu items are all undefined, the setSelectedItem( ) method should try to match the value to a label instead. Additionally, you can create a setSelectedItems( ...

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