Lead Columns 

Definition

Lead columns are columns that have a special significance in the output. Usually you define columns that contain especially important content as lead columns.

Columns that have already been designated by the application as primary key automatically become lead columns in the ALV object model.

The following properties differentiate a lead column from a normal column:

·        Lead columns have a different color. This color is determined by the system.

·        You are able to determine whether a lead column moves when you scroll sideways through the screen like the other columns, or whether it stays where it is.

·         Lead columns can be found in the user’s column set. By default, the user is able to hide lead columns. You are able to prevent users from hiding lead columns.

For all of the following functions, this is valid:

Display type ALV Tool	Classic ABAP list	Full screen	In the Container
Simple, two-dimensional table	Yes	Yes	Yes
Hierarchical-sequential list	Yes
Tree structure		No	No

 

Use

You are able to make the following settings for lead columns:

·        Define the column as a lead column

·        Determine the color of individual cells in the lead columns

·        Prevent lead columns from scrolling

·        Prevent lead columns from being hidden

Defining the Column as a Lead Column

You are able to define any column of the ALV output as a lead column.

Methods

Function	Class	Method
Define lead columns	CL_SALV_COLUMN_LIST	SET_KEY
Check whether a column is a lead column		IS_KEY

Defining a Color in a Lead Column

Lead columns have their own background color that helps you to differentiate between them and the regular columns in your ALV output. This color is determined by the system. You are not able to change the color of the whole column. However, you are able to override the predefined background color for individual cells of the lead column: You define a separate color column, where you specify one of the possible alternative colors for the desired cell. You also use the NOKEYCOL field in the color column to explicitly deactivate the system color.

Methods

Function	Class	Method
Define color column	CL_SALV_COLUMNS_LIST	SET_COLOR_COLUMN
Get color column		GET_COLOR_COLUMN

Prevent Lead Columns from Scrolling

If there is not enough room for all of the columns of the ALV output to be displayed on the screen simultaneously, the user can scroll sideways until the desired column becomes visible.  Usually the other columns disappear when you are doing this. You are able to determine whether the lead columns are fixed, which means that they remain visible when you scroll sideways.

Methods

Function	Class	Method
Fix lead columns	CL_SALV_COLUMNS_LIST	SET_KEY_FIXATION
Checks whether the lead columns are fixed		HAS_KEY_FIXATION

Preventing Lead Columns from Being Hidden

By default, users can hide or display columns that are part of their column set as needed. You are able to prevent users from hiding each lead column individually.

Methods

Function	Class	Method
Prevent lead columns from being hidden	CL_SALV_COLUMN_LIST	SET_KEY_PRESENCE_REQUIRED
Check whether the lead column can be hidden		IS_KEY_PRESENCE_REQUIRED