Notify when a key is pressed

[Luciano França]

In VCL I block when the User presses Enter and does not release the key.
I use the Component

"ApplicationEvents"
using the event "OnMessage"

var
 Form1: TForm1;
 Count_Enter : Integer = 0;
 MostrouMsgTeclaPressionada : Boolean = False;

procedure TForm1.ApplicationEvents1Message(var Msg: TMsg; var Handled: Boolean);

 Procedure P_MensagemKeyPrecionada(Tecla: String);
 Begin
  MostrouMsgTeclaPressionada := True;
  Showmessage('Verifique a Tecla "' + Tecla + '" pois foi precionada muitas vezes e isso não é possivel.');
  MostrouMsgTeclaPressionada := False;
 End;

begin
 if (Msg.message = WM_KEYUP) then 
  Count_Enter := 0;

 if (Msg.message = WM_KEYDOWN) then begin
  if (Msg.wParam = VK_RETURN) Or (Msg.wParam = VK_TAB) then Begin
   
   Inc(Count_Enter);

   if Count_Enter > 1 Then
    if Not MostrouMsgTeclaPressionada Then
      P_MensagemKeyPrecionada('Enter');
      
  end;
 end;

End;

How could I do this in Unigui ?

[Sherzod]

Hello,

Do you want to detect Enter and Tab key presses globally (at the document level), or only within a specific component such as UniMemo?

[Luciano França]

1 hour ago, Sherzod said:

Hello,

Do you want to detect Enter and Tab key presses globally (at the document level), or only within a specific component such as UniMemo?

At a global level in any component, form, etc...

[Sherzod]

1 minute ago, Luciano França said:

At a global level in any component, form, etc...

Just out of curiosity — may I ask what the reason is for detecting Enter and Tab globally?

[Luciano França]

7 minutes ago, Sherzod said:

Just out of curiosity — may I ask what the reason is for detecting Enter and Tab globally?

 

My clients have the habit of pressing a key and holding it down, especially the enter key. Some of my modules show several confirmation messages, so holding it down will confirm all of them. Because of this, in VCL I block the stuck pressing of keys.

[Sherzod]

13 minutes ago, Luciano França said:

Because of this

Could you review this code and let us know if it suits your needs?

MainForm.Script ->

// Timestamps for the last Enter and Tab key press
let lastEnterTime = 0;
let enterCount = 0;

let lastTabTime = 0;
let tabCount = 0;

// Timers to reset counters after a delay
let timerEnter = null;
let timerTab = null;

// Global keydown event listener
document.addEventListener('keydown', function (e) {
  const now = Date.now();

  // === ENTER logic ===
  if (e.key === 'Enter') {
    // If key pressed again within 500ms, consider it repeated
    if (now - lastEnterTime < 500) {
      enterCount++;
    } else {
      enterCount = 1; // Reset count if delay is too long
    }
    lastEnterTime = now;

    // Show warning after 5 fast presses
    if (enterCount >= 5) {
      alert('You are pressing Enter too often. Please be careful.');
      enterCount = 0;
    }

    // Reset enter counter after 1.5 seconds of inactivity
    clearTimeout(timerEnter);
    timerEnter = setTimeout(() => { enterCount = 0; }, 1500);
  }

  // === TAB logic ===
  if (e.key === 'Tab') {
    if (now - lastTabTime < 500) {
      tabCount++;
    } else {
      tabCount = 1;
    }
    lastTabTime = now;

    if (tabCount >= 5) {
      alert('You are pressing Tab too often. Please stop.');
      tabCount = 0;
    }

    clearTimeout(timerTab);
    timerTab = setTimeout(() => { tabCount = 0; }, 1500);
  }
});

 

[Luciano França]

fantastic perfect  

 

Edited May 4, 2025 by Luciano França