By including the %M% directive in the definition of a list box, you convert the list box from a single-select to a multi-select control. For example, the following script allows you to select multiple cities:

By including the %C=column width% directive in the definition of the list box control, you can specify that the list box should be displayed in multiple columns. For example, the following specifies a list box control that has 3 columns, each 30 characters wide (the list box width is 90 characters).

Multi-Select Queries provides a technique for building queries that select a set of records by record number. To use Multi-Select:

One or more Multi-Select List Box objects may appear inside the Format section of a UI_DLG_BOX() function. The selections are stored in the %mw% variable.

If you want to present a user with a list of options that allows multiple selections, the following alternatives are easy to implement. Both alternatives are variations of a single design and both assume that you can subsequently use a character list of the selected options.

When multiple items are selected, the ME directive causes a multi-select list box to place the value that has focus at the beginning of the list that it returns.

The MW directive populates the List Box with the selections of a Multi-Select List Box. The Choices argument is not used in the List Box Control Syntax. When you have multiple directives in a Format string, you separate them with semi-colons ";".

The M directive defines a multiple selection list box. When you have multiple directives in a Format string, you separate them with semi-colons ";".

The H directive allows horizontal scrolling in a list box.  When you have multiple directives in a Format string, you separate them with semi-colons ";".

The C directive defines the multiple column structure of a multi-column list box.  When you have multiple directives in a Format string, you separate them with semi-colons ";".