Unit
IB_Grid

Declaration
TIB_CustomCombo = class(TCustomEdit)

Description
This control is used to provide an easy way for users to define cross dataset relationships. All of the handling of the key values is done in the dataset behind the scenes.

This control takes a significantly different approach than other lookup controls. This is because most of the dataset to dataset relationship handling is built in to the dataset class itself.

The relationship is defined using the KeyLinks and KeySource properties. Please refer to these for more assistance.

As long as the DisplayField property is the same as the OrderingLink of the lookup dataset it will be possible to use incremental searching.

It is case sensitive by default but if the column the lookup dataset is currently ordered by has a NOCASE entry in the column attributes then the incremental searching will be made case insensitive for you automatically.

It is also possible to leave the DisplayField property blank and have it automatically display the OrderingLink value. Thus, if there are multiple columns defined in the OrderingLinks property of the lookup dataset and the popup list allows the OrderingItemNo to be changed by clicking on the title of the popup list the control will then display the value from newly ordered column.

Thus, by leaving the DisplayField property blank and only allowing the ordering of the lookup dataset to be done with a valid OrderingLink a very flexible and functional control is realized.

Keep in mind that this control will work even with very large datasets. In order to do this though it is necessary to tune the OrderingLinks property for the lookup dataset. I have used it on a query against a table of 100K rows+ over a modem at 28K with acceptable performance.

There is a sample application for this control as well as defining KeyLinks.

Introduced Public Properties

AllowTimeout	This property determins if the incremental search string will time out after a certain period of time defined by the dataset.
AutoDropDown	This property causes the grid to automatically drop down when search criteria is being entered.
CanDropDown	Property which gives additional control over whether or not the popup list drops down.
ColLines	Property access to the popuplist.
CustomPopup	This property allows a separate TIB_LookupList component to be used instead of the default popup list.
DataSource	Reference to the dataset to which this control is bound.
DefaultRowHeight	Property access to the popuplist.
DisplayField	The field that is to be displayed in the edit portion of the control.
DropDownAlign	This property is obsolete.
DropDownCount	Number of rows in the popup list when dropped down.
DropDownWidth	Width in pixels of the popup list when dropped down.
FixedColLines	Property access to the popuplist.
FixedRowLines	Property access to the popuplist.
GridLinks	This allows a custom list of columns to appear in the default popup list.
IgnoreColorScheme	This property causes the control to ignore the coloring scheme and allow its color to be maintained manually by the application developer.
IndicateOrdering	Property access to the popuplist.
IndicateRow	Property access to the popuplist.
IndicateSelected	Property access to the popuplist.
IndicateTitles	Property access to the popuplist.
IsDroppedDown	Property to tell if the popup listbox is visible or not.
OnPrepareSQL	This event allows for custom alterations to be made to the SELECT statement's WHERE clause at prepare time.
PopupAlignment	Property to align the PopupList puAuto : = puLeft if enough place to display completely else = puParentRight puLeft : PopupList always left aligned to the Combobox puRight : PopupList always right aligned to the Combobox puCentered : PopupList always vertically centered to the Combobox puParentLeft : PopupList always left aligned to Parent.Combobox puParentRight : PopupList always right aligned to Parent.Combobox puParentCentered : PopupList always vertically centered to Parent.Combobox
PopupColor	Colorwhich gets applied to the default popup list that is used internally.
PopupFixedColor	Property to preset the color of the fixed fields in the default PopupList
PopupList	Direct reference to the popup list being used.
PreventDeleting	Determines if the control can initiate the deletion of records.
PreventEditing	Determines if any editing changes can be made through this control.
PreventInserting	Determines if any inserting changes can be made through this control.
PreventSearching	Determines if any search criteria changes can be made through this control.
ReadOnly	Determins if any modifications can be entered through this control.
RowLines	Property access to the popuplist.
ScrollBars	Property to control the ScrollBars setting of the popup grid.
SearchKeyByKey	When searching is being performed against a text based column it is possible to have the search begin operating a character at a time as they are pressed.
SearchText	The text that has been typed in for performing incremental searching on.
SeekNearest	Determines if the nearest record should be selected as the current record or not.

Introduced Public Methods

CanModify
ClearSelection	Method to make the LookupCombo display empty in the same way as if the user pressed the DEL key with the control focused.
CloseUp	Method to cause the popup list to close up.
Create
Destroy
DropDown	Method to cause the popup list to drop down.

Introduced Public Events

OnCloseUp	This event is triggered whenever the popuplist is being closed up.
OnDropDown	This event allows a custom action to be taken prior to the dropping down of the popuplist.
OnNotInList	This property is used to take action on an item that was not found in the lookup dataset.
OnSelectionCleared	This event is triggered after the LookupCombo's value is cleared, which occurs when the user presses the DEL key or when the developer calls the ClearSelection method.