HELP: what´s wrong with this SIMPLE CODE?

joelrodrigues · Beiträge: 20

Hi folks,

I am developing an application that captures Keyboard keys pressed and mouse actions and display them on the screen ... For this, i have two hooks (WM_KEYBOARD and WM_MOUSE), each one in its own DLL (MouseHook.dll and KeyHook.dll).

MouseHook has the following procedure:

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// declaration
procedure OnMouseEvent(Sender: TObject; AMouseStates: TMouseStates);

// implementation
procedure TForm1.OnMouseEvent(Sender: TObject; AMouseStates: TMouseStates);
begin
  if ((AMouseStates.ButtonInfo = WM_LBUTTONDOWN)) then
  begin
    Label1.Caption := 'Left Mouse Button pressed';
  end;
end;

KeyHook has the following procedure:

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// declaration
procedure OnKeyPressed(Sender: TObject; AKeyStates: TKeyStates; AKeyNames: TKeyNames);

// implementation
procedure TForm1.OnKeyPressed(Sender: TObject; AKeyStates: TKeyStates; AKeyNames: TKeyNames);
begin
  if AKeyStates.KeyDown then   // i need check if the (AMouseStates.ButtonInfo = WM_LBUTTONDOWN)
  begin
    Label1.Caption := 'Key Pressed';
  end;
end;

I need change the Label1.Caption to "Key Pressed and Left Mouse Button pressed" when the user press a key and the left mouse button simultaneously.

So, i am trying change the line "if AKeyStates.KeyDown then" (inside the OnKeyPressed procedure) to something like this:

KeyHook has the following procedure:

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// declaration
procedure OnKeyPressed(Sender: TObject; AKeyStates: TKeyStates; AKeyNames: TKeyNames);

// implementation
procedure TForm1.OnKeyPressed(Sender: TObject; AKeyStates: TKeyStates; AKeyNames: TKeyNames);
begin
  if (AKeyStates.KeyDown) and (AMouseStates.ButtonInfo = WM_LBUTTONDOWN) then   // line changed
  begin
    Label1.Caption := 'Key Pressed and Left Mouse Button pressed';
  end;
end;

But, when i changed that line, Delphi says: "Undeclared identifier: 'AMouseStates' ...

What´s wrong with my code?

Any help or comments will be deeply appreciated.

Best regards and happy new year...

JOEL RODRIGUES

Moderiert von Gausi: Delphi-Tags hinzugefügt

Marco D. · Verfasst: Mo 01.01.07 13:50

'AMouseStates' is only declared in the procedure:

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1:	procedure TForm1.OnMouseEvent(Sender: TObject; AMouseStates: TMouseStates);

So you have to save the MouseState in another variable:

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// implementation

var LeftMouseDown: boolean;
procedure TForm1.OnMouseEvent(Sender: TObject; AMouseStates: TMouseStates);
begin
  if ((AMouseStates.ButtonInfo = WM_LBUTTONDOWN)) then
  begin
     Label1.Caption := 'Left Mouse Button pressed';
     LeftMouseDown := true;
  end
  else LeftMouseDown := false;
end;

So you can check if the left mouse button is pressed:

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// implementation
procedure TForm1.OnKeyPressed(Sender: TObject; AKeyStates: TKeyStates; AKeyNames: TKeyNames);
begin
   if (AKeyStates.KeyDown) and (LeftMouseDown = true) then
   begin
     Label1.Caption := 'Key Pressed';
   end;
end;

Hope that is helpful.

_________________
Pascal keeps your hand tied. C gives you enough rope to hang yourself. C++ gives you enough rope to shoot yourself in the foot

joelrodrigues · Beiträge: 20

OH, so fast!!! That´s why i appreciated german programmers! (Crytek rules!

Ich denke nicht Deutsche aber ich will warum you are really good programmers!

Thanks very much MARCO D!

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