How Can I Enable Keyboard Navigation and Focus on a Custom Panel Control?

Custom controls solve the panel focus problem

In the process of adding keyboard navigation to a custom graphics program, the user encountered the problem that the panel control could not receive focus. Although the panel derived events have been overridden, the keyboard and focus events are still not firing.

To do this, an experienced programmer introduced a new user control: SelectablePanel. This control inherits from Panel, with key modifications added to enable focus and keyboard input handling.

SelectablePanel enhanced functions

• Focus Control: Use the SetStyle method of the control to set the Selectable style so that it can receive focus. Additionally, set TabStop to true.
• Accept keyboard input: Override the IsInputKey method to recognize the cursor keys (up, down, left, right) as input.
• Visual focus indication: Override the OnEnter and OnLeave events to draw the focus rectangle when the control has focus.

Achievement

The

SelectablePanel class overrides the default panel behavior and introduces custom event handling. The OnMouseDown event is used to force focus to the panel. An override of IsInputKey enables handling of cursor keys.

How to use

In your application, replace the standard Panel control with an instance of SelectablePanel. This will provide both keyboard navigation and focus indication.

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