TCustomUtilityButton.OnClick Event

Occurs when the user clicks the control.

Pascal

property OnClick: TNotifyEvent;

C++

__property TNotifyEvent OnClick;

Description

Use the OnClick event handler to respond when the user clicks the control. If the control has an associated action, and that action has an OnExecute method, the action's OnExecute method responds to click events unless it is superseded by an OnClick event handler.

Usually OnClick occurs when the user presses and releases the left mouse button with the mouse pointer over the control. This event can also occur when:

The user selects an item in a grid, outline, list, or combo box by pressing an arrow key.
The user presses Spacebar while a button or check box has focus.
The user presses Enter when the active form has a default button (specified by the Default property).
The user presses Esc when the active form has a cancel button (specified by the Cancel property).
The user presses the accelerator key for a button or check box. For example, if the value of the Caption property of a check box is '&Bold', the B is underlined at runtime and the OnClick event of the check box is triggered when the user presses Alt+B. However, focus does not move to the control in these instances.
The Checked property of a radio button is set to true.
The value of the Checked property of a check box is changed.
The Click method of a menu item is called.

For a form, an OnClick event occurs when the user clicks a blank area of the form or on a disabled component.

C++ Examples:

Copy Code

/*
This examples requires a TPageControl and a TCheckBox.  The
form OnCreate event handler populates each sheet with an
edit control placed somewhere on the client area of the
sheet.  Unchecking the checkbox will cause the client area
(not the tab area) of the Tab Control to become invisible.
*/
void __fastcall TForm1::PageControl1Change(TObject *Sender)
{
  CheckBox1->Checked = PageControl1->ActivePage->Visible;
}

void __fastcall TForm1::CheckBox1Click(TObject *Sender)
{
  PageControl1->ActivePage->Visible = CheckBox1->Checked;
}

void __fastcall TForm1::FormCreate(TObject *Sender)
{
  for (int i = 0; i < 10; i++)
  {
    TTabSheet *pPage = new TTabSheet(this);
    pPage->PageControl = PageControl1;
    pPage->Caption = AnsiString("Page") + IntToStr(i);
    TEdit *pEdit = new TEdit(this);
    pEdit->Parent = pPage;
    pEdit->Left = random(pPage->ClientWidth - pEdit->Width);
    pEdit->Top = random(pPage->ClientHeight - pEdit->Height);
  }
  PageControl1Change(Sender);
}

Delphi Examples:

Copy Code

{
This examples requires a TPageControl and a TCheckBox.  The
form OnCreate event handler populates each sheet with an
edit control placed somewhere on the client area of the
sheet.  Unchecking the checkbox will cause the client area
(not the tab area) of the Tab Control to become invisible.
}
procedure TForm1.CheckBox1Click(Sender: TObject);
begin
  PageControl1.ActivePage.Visible := CheckBox1.Checked;
end;

procedure TForm1.PageControl1Change(Sender: TObject);
begin
  CheckBox1.Checked := PageControl1.ActivePage.Visible;
end;

procedure TForm1.FormCreate(Sender: TObject);
var
  i: Integer;
begin
  for i := 0 to 9 do
    with TTabSheet.Create(Self) do
    begin
      PageControl := PageControl1;
      Caption := 'TabSheet' + IntToStr(i);
      with TEdit.Create(Self) do
      begin
        Parent := PageControl1.Pages[i];
        Left := Random(PageControl1.ActivePage.ClientWidth - Width);
        Top := Random(PageControl1.ActivePage.ClientHeight - Height);
      end;
    end;
    PageControl1Change(Sender);
end;