Tree and list control supporting data entry and user defined cells

Ancestors - Control (PRIM_CTRL) Object (PRIM_OBJT)

Details

The List control is a highly functional list that supports tree structures, data entry and user defined cell content.
 
In its simplest form, List is a typical two dimensional column based LANSA list control managed by the LANSA list commands, such as ADD_ENTRY, GET_ENTRY, SELECTLIST etc. Each column has a source field and data values are mapped in and out of the list as items are used.
 
List can also be used as a tree. List Items can be parented to other list items and the List control will manage the appearance, expanding and collapsing items as required.
 
Unlike other LANSA list controls such as Tree and Grid which use a single column type, List has specific column types to support the different types of content. This extends beyond the typical field based columns to include image, check box, button and reusable part.
 
Supported column types - string, number,  date time, image, button, check box and reusable part.
 
List also supports the use of dataless columns. For example, a list may consist of nothing more that checkboxes if required. Rather than relying on field values the column currentitem property can be accessed.
 
Columns work in 2 ways. Firstly, the definition of the column is used as a prototype when an entry is added. So, a button column defined with a caption of "Delete" will show a button in each item with a caption of "Delete". Secondly, all column types have a CurrentItem property that provides access to the individual instance.
 
List is also used as the basis for the DropDown control. The result is that all the features available in list are also available in the drop down area of DropDown.
 
Note: Execution in the browser does not lend itself to high volumes of data. Adding thousands of entries to a list will impact performance. Instead, you should use improved filtering, page at a time and load on demand strategies to ensure that the data is limited.

Example

This example shows a simple list with a number and button columns. The button is hidden if the row is an even numbered row. Clicking the button will delete the row.

Begin_Com Role(*EXTENDS #PRIM_WEB) Height(456) Width(864) Layoutmanager(#TableLayout1)
   Define_Com Class(#PRIM_TBLO) Name(#TableLayout1)
   Define_Com Class(#PRIM_TBLO.Column) Name(#Column1) Displayposition(1) Parent(#TableLayout1)
   Define_Com Class(#PRIM_TBLO.Row) Name(#Row1) Displayposition(1) Parent(#TableLayout1)
   Define_Com Class(#PRIM_TBLO.Item) Name(#List1Item1) Column(#Column1) Manage(#List) Parent(#TableLayout1) Row(#Row1)
 
   Define_Com Class(#PRIM_LIST) Name(#List) Displayposition(1) Left(0) Parent(#COM_OWNER) Tabposition(1) Top(0) Height(456) Width(864) Rowheight(33)
   Define_Com Class(#PRIM_LIST.Number) Name(#ColumnXDEMONUMB1) Displayposition(1) Increment(1) Parent(#List) Source(#xDemoNumber) Wrap(False)
   Define_Com Class(#PRIM_LIST.Button) Name(#ColumnButton1) Columnwidth(100) Displayposition(2) Parent(#List) Caption('Delete') Cellsizing(None) Cellwidth(80)
 
   Evtroutine Handling(#Com_Owner.CreateInstance)
 
      Begin_Loop Using(#xDemoNumber) To(10)
 
         Add_Entry To_List(#List)
 
         #ColumnButton1.CurrentItem.Visible := (#xDemoNumber.mod( 2 ) = 0)
 
      End_Loop
 
   Endroutine
 
   Evtroutine Handling(#ColumnButton1.Click)
 
      Dlt_Entry Number(#List.CurrentItem.Entry)
 
   Endroutine
 
End_Com

Properties

Events

Methods

See also

All Component Classes

Technical Reference

EPC1420030 V14sp2 November 2018