1. Keyboards, Pages & TransformsBy
Yi-Yang Huang
&
Jayashree Venkatesh

2. Ignoring the keyboard
Microsoft windows and windows forms class handle many keyboard functions themselves.
Ignore keystrokes in menu selection.
Windows forms programs define keyboard accelerators to invoke common menu items.
Dialog boxes also have a keyboard interface, but programs need not monitor the keyboard when a dialog box is active.

3. Who’s got the focus?
A particular keystroke has only a single destination, which is of type Control or a descendant of Control, such as Form.
Active form is usually the topmost form on the desktop.
Active form is available from the only static property implemented by Form.
Type : Form Property : ActiveForm Accessibility : get

4. Form Methods (selection) void Activate() Form Events (selection)
Event Method Delegate Argument
Activated OnActivated EventHandler EventArgs
Deactivate OnDeactivate EventHandler EventArgs

5. Keyboards and Characters
Keyboard can be
A collection of distinct physical keys
A means of generating character codes (Unicode).
Four groups of keys
Toggle keys (Caps, Num, Scroll locks, Insert)
Shift keys (Shift, Ctrl, Alt)
Noncharacter keys (function, pause, del)
Character keys (letter,no,Tab,Backspace,Enter,Esc)

6. Keys Down and Keys Up Control Events (selection)
Event Method Delegate Argument
KeyDown OnKeyDown KeyEventHandler KeyEventArgs
KeyUp OnKeyUp KeyEventHandler KeyEventArgs
protected override void OnKeyDown (KeyEventArgs kea) { … }

7. protected override void OnKeyUp (KeyEventArgs kea){ … }
Void MyKeyDownHandler (object objSender, KeyEventsArgs kea)
Void MyKeyUpHandler (object objSender, KeyEventsArgs kea)

8. cntl.KeyDown += new KeyEventHandler (MyKeyDownHandler);
cntl.KeyUp += new KeyEventHandler (MyKeyUpHandler);
KeyEventArgs Properties
Type Property Accessibility
Keys KeyCode get
Keys Modifiers get
Keys KeyData get
Bool Shift get
Bool Control get
Bool Alt get
Bool Handled get/set
Int KeyValue get

9. Keys Enumeration Keys has 26 members Keys Enumeration (letters)
A – 65 , B – 66 , ….., Z – 90
Keys Enumeration(numbers)
D0 – 48, D1 – 49 ….D
Keys Enumeration (function keys)
F1 – 112, F2 – 113….F24 – 135.

10. Keys Enumeration (keypad operators)
Multiply – 106, Add – 107, Subtract – 109, Divide – 111
Also of Keys Enumeration are the foll:
Keypad unused - Separator
Keypad cursor movement – Home, Left, End, Insert, Up, Clear, Down, Right, Pageup / Pagedown, Right, Delete
ASCII control keys – Back, Tab, Linefeed, Enter Return, Escape, Space
Shift keys – Shift, Control , Menu, LShiftkey, Lcontrolkey, LMenu, RShiftkey, RControlkey,RMenu

11. Microsoft keys – LWin, RWin, Apps
Miscellaneous – Cancel, Pause, Capslock, Printscreen, Numlock, Scroll
Mouse buttons – LButton, RButton, MButton
Special keys – Select, Print, Execute, Help, Processkey, Attn, Play, Zoom
Symbols – Oemsemicolon, Oemplus, Oemcomma, Oemminus, Oemperiod, OemQuestion, Oemtilde, OemPipe, Oemquotes, Oembackslash

12. Browsers and players – browserback, browserforward, browserrefresh, browserstop,…., volumemute, volumedown, volumeup,..,launchapplication1,…,mediastop,…
IME (Input method editor) – Finalmode, Kanjamode, IMEconvert,IMEaccept….
Modifier keys – none,shift,control, alt
Eg: Shift followed by D
Masks are provided for differentiating the keycodes and modifiers.

13. Testing the modifier keys
State of modifier keys can also be obtained using the static Control.ModifierKeys property.
Keys keysmod =Control.ModifierKeys
If (keysMod == (Keys.Shift | Keys.Control))
{ // Shift and Ctrl and pressed }
If (keysMod == Keys.Shift)
{ // Shift is pressed }
If (keysMod == Keys.Control))
{ // Ctrl is pressed }

14. Reality check Problems with Capslock
KeyDown is mostly used for cursor movement, Insert and Delete
KeyPress for Characters
Control Events(selection)
Event Method Delegate Argument
KeyPress OnKeyPress KeyPressEventHandler KeyPressEventArgs

15. KeyPressEventArgs Properties
Type Property Accessibility
char KeyChar get
bool Handled get/set
Control Characters
Keyboard-Generated Control Characters
Key Control Character
Shift x0000
Backspace x0008
…….

16. Platform Invocation Services ScrollWindow:
Invoking the Win32 API
Platform Invocation Services
ScrollWindow:
Bool Scrollwindow(HWND hwnd, int Xamount, int Yamount, const RECT * lprect.CONST RECT * lpclipRECT);
Typedef struct tagRECT {
Long left;
Long top;
Long right;
Long bottom;
}RECT;

17. Handling input from foreign keyboards
Control panel – regional options – general tab – change the language settings – reboot
Input focus
Determines which control gets keyboard input.
Control Properties (selection)
Type Property Accessibility
bool CanFocus get
bool ContainsFocus get
Bool Focused get

18. Control Methods (selection)
Bool Focus ( )
Control Events(selection)
Event Method Delegate Argument
GotFocus OnGotFocus EventHandler EventArgs
The Missing Caret
Cursor is instead referred in Windows as a caret.
Caret caret = new Caret (form);

19. Caret Properties
Type Property Accessibility
Control Control get
Size Size get/set
Point Position get/set
Bool Visibility get/set
size of Caret : Caret.Size = new Size( 2, Font.height);
Caret Methods :
Void Hide();
Void Show();
Void Dispose();

20. protected override void OnGotFocus (EventArgs ea){
Base.OnGotFocus(ea); … }
protected override void OnLostFocus (EventArgs ea)
Base.OnLostFocus(ea);