CL_GUI_LIST_TREE - List Tree Control

SUBST_MERGE_LIST - merge external lists to one complete list with #if... logic for R3up   rdisp/max_wprun_time - Maximum work process run time  
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Functionality

The class CL_GUI_LIST_TREE is a wrapper for the list tree control (LIST_TREE). A list tree control has the following attributes:

• It has no columns.

• Each node can have any number of items. The items are displayed from left to right.

• Each item has an individual length.

Example program: SAPTLIST_TREE_CONTROL_DEMO.

Important Notes

• If you try and send too many nodes to the tree control during one PAI/PBO round trip, a timeout may occur.

• If you want to change several components (for example, 20 texts), you should use a method with atable interface (update_...) instead of calling a single method 20 times. This also applies for other operations such as expanding nodes.

• In a PAI/PBO cycle, you should not repeatedly call methods with table parameters. For example: Insteadof calling ADD_NODES_... 20 times with 5 methods in each call, it is more efficient to call it once with all 100 nodes.

• The exceptions of the tree control do not set a message.

• The exceptions of the tree control methods and flush calls must not be ignored. If an error occurs,the entire automation queue processing is terminated, which affects ALL controls in the same internal session. Once an error has occurred, the internal session must not continue working with controls.

• The tree control is not suitable for displaying lists without a hierarchy, since all root nodesof a structure must always be transferred to the control. Consequently, lists with large numbers of entries could lead to performance problems.

Troubleshooting

If a program that worked previously suddenly no longer works, you should first check whether the tree control examples still work.

The most frequent errors in control processing occur with FLUSH calls: Method CL_GUI_CFW=>FLUSH (orfunction module CONTROL_FLUSH in the old Control Framework), exception CNTL_ERROR. This exception onlytells you that something has gone wrong with the control at the frontend. In fact, the error may not even have occured in the tree control, but in another control (wrongly-used method calls, for example).

Troubleshooting falls into two sections:

• A control error occurs in the program.

• Restart the program in the Debugger, and choose "Settings" from the Debugger screen. Select theoption "Automation controller: Always process requests synchronously". The control methods now returnmore precise information about the cause of the error (if the error occured in the tree control at all).For example, the method SELECT_NODE will now return the exception NODE_NOT_FOUND if the node the user tried to select is not in the tree.

Relationships

Example

Notes

Further information

BAL Application Log Documentation   Vendor Master (General Section)  
This documentation is copyright by SAP AG.


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