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Article #16337: Controlling shortcut keystrokes in a string grid

 Question and Answer Database

FAQ1337D.txt   Controlling shortcut keystrokes in a string grid
Category   :Windows API
Platform    :All
Product    :All 32 bit  

Question:
I have a string grid that is read only. I am trapping any
keystrokes sent to the string grid. I have a button that has a
caption of E&xit. When ever the user presses the x key (even if
the alt key is not pressed) in the string grid, the button
click is executed. How can I prevent this?

Answer:
The following example demonstrates trapping the CM_DIALOGCHAR
message at the form level. This will give you an opportunity to
respond to a dialog character only if the alt key is held down,
preventing the default handeling of the character shortcuts.

Example:

type
  TForm1 = class(TForm)
    Button1: TButton;
    StringGrid1: TStringGrid;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure StringGrid1KeyDown(Sender: TObject; var Key: Word;
      Shift: TShiftState);
  private
    { Private declarations }
    procedure CMDialogChar(var Message: TCMDialogChar);
      message CM_DIALOGCHAR;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.FormCreate(Sender: TObject);
begin
  Button1.Caption := 'E&xit';
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  Application.Terminate;
end;

procedure TForm1.StringGrid1KeyDown(Sender: TObject; 
var Key: Word; Shift: TShiftState);
begin
  ShowMessage('Grid keypress = ' + Char(Key));
  Key := 0;
end;

procedure TForm1.CMDialogChar(var Message: TCMDialogChar);
begin
  if ssAlt in KeyDataToShiftState(Message.KeyData) then
    inherited;
end;

7/16/98 4:31:28 PM
 

Last Modified: 01-SEP-99