Essential Component Properties and Event Handling Techniques

Fundamental Component Configuration and Interaction

Defining and Displaying the Context Menu

The context menu is created using the PopUpMenu component. To ensure it appears correctly when clicked on a form, you must set the form's PopupMenu property to reference the created PopUpMenu component.

Purpose of the Execute Method

The Execute method is used to create and display a dialog box.

Execute Method Return Values and Conditions

The Execute method returns a Boolean value:

• True is returned if the user:
  • Triggers the OK button.
  • Double-clicks a file name.
  • Presses Enter on the keyboard.
• False is returned if the user:
  • Triggers the Cancel button.
  • Presses Esc.
  • Closes the dialog box.

Defining Short and Long Component Hints

Hints (short and long tips) are defined using the Hint property, typically formatted as Short Hint | Long Tip.

• To display the short tip, set the component's ShowHint property to True.
• To display the long tip, set the AutoHint property of the status bar (StatusBar) component to True.

Understanding the Enabled Property

Components can be enabled or disabled using the Enabled property:

• Setting it to True activates the component.
• Setting it to False disables the component.

A disabled component cannot receive focus (e.g., it cannot be clicked or interacted with).

Defining TabOrder and BorderStyle Properties

• TabOrder: Defines the component's position within the sequential tab navigation order.
• BorderStyle: Defines the type of edge or border style. If set to bsNone, the form will be borderless, blending into the background.

When Do OnChange and OnClick Events Occur?

• OnChange: Triggered when the content of a control changes (e.g., modifying the Text property of an Edit component).
• OnClick: Triggered when the component is activated using a mouse button.

Common Keyboard Events Triggered by Controls

• OnKeyUp: Occurs when a key is released.
• OnKeyPress: Fired when the user presses a key. This event typically only handles alphanumeric keys, Tab, Backspace, Enter, or Esc.
• OnKeyDown: Fired when the user presses a key while the control has focus.

Creating a Toolbar and Assigning Bitmaps

1. Create the toolbar using the ToolBar component.
2. Insert an ImageList component to manage the bitmaps.
3. Populate the ImageList with the required images in the desired display order.
4. Set the ImageList property of the ToolBar component to reference the name of the created ImageList component. The images will then appear on the toolbar buttons.