- Table control with direct access to the data source
- Table control populated programmatically
- Table control with in-memory data source
11. Table/Looper controls
Table/Looper controls can be used to display a set of information (e.g., the content of a data file). The content of these controls can come from different sources:
- Table/Looper control with direct access to the data source.
- Table/Looper control populated programmatically.
- Table/Looper control with in-memory data source.
: These three modes will be explained in detail for the Table control. However, the same concepts apply to the Looper control.
Table control with direct access to the data source
A Table control with direct access to the data source displays data directly from a data file, query or array variable. When you loop through the data file, the data is displayed in the Table control. The data file is read for each row displayed: the record that is read is displayed in a row of the Table control.
The displayed data that is not linked to the data file is lost when the row is refreshed (e.g., value of a check box column).
The number of records displayed in the control can be limited by setting a filter (HFilter
used in the control initialization code).
The WLanguage functions starting with "Table" are used to handle Table controls with direct access to the data source. When a row is added to or deleted from the Table control, the record in the bound data file is also added or deleted.
Table control populated programmatically
In this case, the Table control directly displays the data loaded in memory. The data is added to the Table control through programming (using TableAddLine
, for example).
Since the data is in memory, you can perform different types of operations on the Table control (e.g., sort or search for data in the columns, etc.).
Table control with in-memory data source
Table controls with in-memory data source combine the advantages of Table controls with direct access to the data source and Table controls populated programmatically.
The Table control is linked to the data file but all the contents of the data file are loaded in memory. Sort and the search features are available for all columns.
The data that is not linked to the data file (Check Box columns, for example) is not lost when scrolling the Table control.
Since data file records are loaded in memory, this type of Table control is recommended for data files with less than 100,000 records (to avoid memory overflow).Remark
: The different modes to populate the controls (programmatically, with direct access to the data source and with in-memory data source) are available for different types of controls: List Box, Combo Box, Table, Looper, etc.
|Table controls are not available in Universal Windows Platform apps. Only Looper controls are available.|
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