Winforms Keyboard Sınıfı

isKeyDown metodu
Şöyle yaparız.

if ((Keyboard.IsKeyDown(Key.LeftCtrl) )
{
  ...
}

Winforms MaskedTextBox Sınıfı

Mask Alanı
Şöyle yaparız.

0 - Digit, required. Value between 0 and 9.
9 - Digit or space, optional.
# - Digit or space, optional. If this position is blank in the mask, it will be rendered
 as a space in the Text property.
L - Letter, required. Restricts input to the ASCII letters a-z and A-Z.
? - Letter, optional. Restricts input to the ASCII letters a-z and A-Z.
& - Character, required.
C - Character, optional. Any non-control character.
A - Alphanumeric, required.
a - Alphanumeric, optional.
.  - Decimal placeholder.
, - Thousands placeholder.
: - Time separator.
/ - Date separator.
$ - Currency symbol.
< - Shift down. Converts all characters that follow to lowercase.
> - Shift up. Converts all characters that follow to uppercase.
| - Disable a previous shift up or shift down.
\ - Escape. Escapes a mask character, turning it into a literal. "\\" is the escape
 sequence for a backslash.