This component allows users to browse hierarchical tables and queries on both enterprise databases (such as Oracle, Interbase), as well as tables that are files (such as Paradox). The user is able to browse from the top level (root), to the lowest level by opening the relevant branches. This component handles tables with multi-field keys (See the SetSelectedPK and GetSelectedPK methods). Only nodes seen are actually loaded. This browser can handle large tables as long as the number of nodes displayed is not greater than the memory available, or greater than 32K.
Specify the datasource that will provide the data for the lookup browser by using the LookupSource Property. Note that the LookupSource must be connected to either a Query or a Table. If the table is a file (such as Paradox), the key fields must be of type string. Note that this component will not work for queries on tables that are files (if they involve more than one file).
The LookupField property defines which field is displayed in the browser (by default). The user can change this field to any visible field in the dataset by selecting it from the combo box. The DisplayField property defines the field that is displayed in the edit box when the user selects an item in the browser.
Use the StdParentChildJoins property to define the relationship between records and the "parent" of the record. The "child" defined is referred to as the Primary Key, and the "Parent" is referred to as the Parent Key.
The RootCondition property defines the condition that results in the top level being selected.
If the user clicks the right mouse button over a node in the outline, then a popup window displays all visible fields of the selected node and their values. The RtClickDetails property indicates if this feature is enabled or not.
The structure can be changed by dragging and dropping. The underlying tables are updated automatically. The CanUpdate property indicates if this feature is enabled or not.
If the user has types some text into the edit box, and then clicks the button, then the database will be searched for text containing this value in the LookupField. Only the relevant branches are opened and the item selected. The SearchEnabled property indicates whether this feature is enabled or not.
The button can be customised by using the BtnCaption, BtnGlyph and NumGlyphs properties. These properties allow the pictures on the buttons to be customised.
Before using this component, you need to define fields for the dataset. To do this, right click your mouse over the table or query, then select 'Fields Editor'. Next, select 'Add' and then add the fields that you would like to include in the browser. Be sure to include the fields that are part of the joins. Fields that are not to be displayed in the browser but are required for joins can be removed by setting the visible property of these fields to false. Set the displayText property of these fields to provide meaningful descriptions of the fields to the user.
Since this component is derived from TEdit, it contains all methods, events and properties that TEdit contains.
TLookupOutline Component Description
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This component is a data aware version of the TOutlineBrowser component. In addition to the multi-field key feature of TOutlineBrowser, TLookupOutline supports multi field joins between the LookupSource and the DataSource for the component. At the same time, the edit box displays a descriptive field (defined by DisplayField) from the LookupSource which represents the join between the two tables.
Use the ForeignJoins property to define the joins between the dataset linked to the LookupSource and the dataset linked to the DataSource Property.
Since this component is derived from TOutlineBrowser, it contains all properties, events, and methods of TOutlineBrowser.
Setting Up the components
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1) Create a directory to house the components
2) Extract the contents of the file into this directory
3) Add the components to the components palette (StdComps.dcu and Olbrowse.dcu). Ensure that you do not have more than one copy of StdComps.
4) Copy the dept.db and personel.db files into the directory for DBDemos (for the demo)
5) Run HelpInst.exe in the help directory in Delphi, add the olbrowse.kwg file to the list, then save. If you have problems with the location of the olbrowse.kwg file, you may need to copy them into this directory. You may need to copy olbrowse.hlp into the Delphi bin directory if you still have problems (as I have)
Once you have done this, you may want to run the demo program to explore the features of the components.
good luck..
About TOutlineBrowser and TLookupOutline
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TOutlineBrowser was written by John Stathakis (e-mail: JLSTATH@MAIL.ICON.CO.ZA)
Version: 1.00 (1996 John Stathakis)
You may use this product freely, however, the source code and related documentation may not be changed in any way without the written permission of the author. Please note that the author will not accept responsibility for any loss resulting from the use of this or any other component. Any code you may recieve may not be distributed in any form without written permision from the author.
Please contact me if you have any enquiries or bug reports.
Note: The author is currently available for employment. Please forward enquiries in this regard to the above e-mail address. Preferred destinations in the following order: Australia, United States, United Kingdom. Other destinations will be considered.
