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Task 9: Add FindKey/FindNearest Functionality Advantage TDataSet Descendant |
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Task 9: Add FindKey/FindNearest Functionality Advantage TDataSet Descendant |
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In this task you will add the ability to your application to do a FindKey or FindNearest. FindKey/FindNearest are in general very fast, but they require an index on the key in question. See Seek for more information.
Add Find GroupBox
| • | Choose the Standard tab on the Delphi Component Palette. |
| • | Select a GroupBox component and place it on Form1. |
Object Inspector:
Name - grpbxFind
Caption - Find
Figure 11 - Browser with the New Find GroupBox ... completing your sample application
Add Find Edit Box and Exact Checkbox
| • | Choose the Standard tab on the Delphi Component Palette. |
| • | Select an Edit component and place it in the Find groupbox. |
Object Inspector:
Name - ebFindValue
Text - " (empty string)
| • | Select a CheckBox component and place it in the Find groupbox. |
Object Inspector:
Name - chkbxExact
Caption - Exact
Add Find Button and Code
| • | Choose the Standard tab on the Delphi Component Palette. |
| • | Select a Button component and place it in the Find groupbox. |
Object Inspector:
Name - btnFind
Caption - Find
| • | Double-click the Find button and add the following code to the OnClick event handler: |
procedure TForm1.btnFindClick(Sender: TObject);
begin
if chkbxExact.Checked then
tblCustomer.FindKey( [ebFindValue.Text] )
else
tblCustomer.FindNearest( [ebFindValue.Text] );
end;
Save and Run
| • | Select Save All from the File menu. |
| • | Select Run from the Run menu, or press the [F9] key to build and run your application. |
Congratulations!
Congratulations, you have completed your first Advantage Delphi application!