Legacy Document

Inside Macintosh: More Macintosh Toolbox /

Chapter 4 - List Manager / List Manager Reference

List Manager Routines / Adding and Deleting Columns and Rows To and From a List

LDelColumn

You can use the LDelColumn procedure to delete one or more columns from a list.

PROCEDURE LDelColumn (count: Integer; colNum: Integer; 
                      lHandle: ListHandle);

count

The number of columns to delete, or 0 to delete all columns.

colNum

The column number of the first column to delete.

lHandle

The list from which to delete the columns.

DESCRIPTION

The LDelColumn procedure deletes the number of columns specified by the count parameter, starting at the column specified by the colNum parameter.

If the column specified by colNum is invalid, then nothing is done.

Your application can quickly delete all columns from a list (and thus delete all cell data) simply by setting the count parameter to 0. The number of rows is left unchanged. Your application can achieve the same effect by setting the colNum parameter to lHandle^^.dataBounds.left and setting the count parameter to a value greater than lHandle^^.dataBounds.right - lHandle^^.dataBounds.left.

Columns whose column numbers are initially greater than colNum have their column numbers decreased by count.

If the automatic drawing mode is enabled and one or more of the columns deleted by LDelColumn are visible, then the list (including its scroll bars) is updated.

SPECIAL CONSIDERATIONS

You should not call the LDelColumn procedure from within an interrupt, such as in a completion routine or VBL task.

ASSEMBLY-LANGUAGE INFORMATION

The trap macro and routine selector for the LDelColumn procedure are

Trap macro	Selector
_Pack0	$0020