TMenuItem.OnClick Event

Occurs when the user clicks menu item.

Pascal

property OnClick: TNotifyEvent;

C++

__property TNotifyEvent OnClick;

Description

Write an OnClick event handler to implement the desired behavior for when the user selects the menu item. An advantage of using the OnClick event handler over directly handling WM_COMMAND messages sent when the user selects the menu item, is that only the OnClick event occurs when the Click method is called.

Note: This event handler is not stored with the menu item if it is supplied by a TAction object.

C++ Examples:

Copy Code

/*
This example uses several forms. The first form has its
FormStyle property set to MDIForm. The others have their
FormStyle properties set to MDIChild and their Visible
properties set to true. Add a main menu component and name
one of the menu items MyArrangeIcons. This is code for the
MyArrangeIconsClick handler.  When the user chooses the
ArrangeIcons command, minimized child forms are arranged
so that they are evenly spaced and don't overlap.  DO NOT
name the menu items "ArrangeIcons" as that will override
the TForm method.
*/
void __fastcall TForm1::MyArrangeIconsClick(TObject *Sender)
{
  Form1->ArrangeIcons();
}

Copy Code

/*
This example uses two edit boxes and one pop-up menu on a form.
The pop-up menu contains Cut, Copy, and Paste commands. This code
makes the pop-up menu available to both edit boxes:
*/
void __fastcall TForm1::FormCreate(TObject *Sender)
{
  PopupMenu1->AutoPopup = true;
  Edit1->PopupMenu = PopupMenu1;
  Edit2->PopupMenu = PopupMenu1;
}

/*
These are the cut, copy, and paste OnClick events for the commands
on the pop-up menu. Double click on the pop-up menu and add three
TMenuItems.  Then set the captions to "Cut", "Copy" and "Paste".
The names will be automatically set to "Cut1", "Copy1", and
"Paste1".  Then double click on the OnClick events and they will
be named "Cut1Click", "Copy1Click" and "Paste1Click" respectively.
Note: only the selected portion of the string in the edit box will
be copied, cut or replaced.
*/
void __fastcall TForm1::Copy1Click(TObject *Sender)
{
  TComponent *pComponent = PopupMenu1->PopupComponent;
  if (pComponent)
  {
    if (pComponent->ClassNameIs("TEdit"))
      (dynamic_cast<TEdit *>(pComponent))->CopyToClipboard();
    else
      MessageBeep(0);
  }
  else
    MessageBeep(0);
}

void __fastcall TForm1::Cut1Click(TObject *Sender)
{
  TComponent *pComponent = PopupMenu1->PopupComponent;
  if (pComponent)
  {
    if (pComponent->ClassNameIs("TEdit"))
      (dynamic_cast<TEdit *>(pComponent))->CutToClipboard();
    else
      MessageBeep(0);
  }
  else
    MessageBeep(0);
}

void __fastcall TForm1::Paste1Click(TObject *Sender)
{
  TComponent *pComponent = PopupMenu1->PopupComponent;
  if (pComponent)
  {
    if (pComponent->ClassNameIs("TEdit"))
      (dynamic_cast<TEdit *>(pComponent))->PasteFromClipboard();
    else
      MessageBeep(0);
  }
  else
    MessageBeep(0);
}

Copy Code

/*
This example demonstrates how to add and delete menu items
to a popup menu at runtime and assign an event handler to
the OnClick event.  Place a TPopupMenu and three buttons on
the form named "AddButton", "EditButton",  and
"DestroyButton" and add OnClick events to all three buttons.
Put the TPopupMenu in the PopupMenu property of the form.
Place the PopupMenuItemsClick procedure in the TForm1 type
declaration so that it can be used as the method call for
the menu item OnClick event.
*/
void __fastcall TForm1::AddButtonClick(TObject *Sender)
{
    // The owner (PopupMenu1) will cleanup this menu item.
    TMenuItem *NewItem = new TMenuItem(PopupMenu1); // create the new item
    int index = PopupMenu1->Items->Count;
    PopupMenu1->Items->Add(NewItem);// add it to the Popupmenu
    NewItem->Caption = "Menu Item " + IntToStr(index);
    NewItem->Tag = index;
    NewItem->OnClick = PopupMenuItemsClick;// assign it an event handler
    TNotifyEvent();
}

void __fastcall TForm1::PopupMenuItemsClick(TObject *Sender)
{
    TMenuItem *ClickedItem = dynamic_cast<TMenuItem *>(Sender);
    if (ClickedItem)
    {
        switch (ClickedItem->Tag)
        {
            case 0:
            {
                ShowMessage("first item clicked");
                break;
            }
            case 1:
            {
                ShowMessage("second item clicked");
                break;
            }
            case 2:
            {
                ShowMessage("third item clicked");
                break;
            }
            case 3:
            {
                ShowMessage("fourth item clicked");
                break;
            }
        }
    }
}

/*
To edit or destroy an item, grab its pointer via the Items
property.
*/
void __fastcall TForm1::EditButtonClick(TObject *Sender)
{
    const int index = 1;
    TMenuItem *ItemToEdit = PopupMenu->Items->Items[index];
    ItemToEdit->Caption = "Changed Caption";
}

void __fastcall TForm1::DestroyButtonClick(TObject *Sender)
{
    const int index = 2;
    TMenuItem *ItemToDelete = PopupMenu->Items->Items[index];
    delete ItemToDelete;
}

void __fastcall TForm1::FormCreate(TObject *Sender)
{
    const int num_items = 4;
    for (int index = 0; index < num_items; ++index)
    {
        // The owner (PopupMenu1) will cleanup this menu item.
        TMenuItem *NewItem = new TMenuItem(PopupMenu1); // create the new item
        PopupMenu1->Items->Add(NewItem);// add it to the Popupmenu
        NewItem->Caption = "Menu Item " + IntToStr(index);
        NewItem->Tag = index;
        NewItem->OnClick = PopupMenuItemsClick;// assign it an event handler
        TNotifyEvent();
    }
}

Delphi Examples:

Copy Code

{
This example uses several forms. The first form has its
FormStyle property set to MDIForm. The others have their
FormStyle properties set to MDIChild and their Visible
properties set to true. Add a main menu component and name
one of the menu items MyArrangeIcons. This is code for the
MyArrangeIconsClick handler.  When the user chooses the
ArrangeIcons command, minimized child forms are arranged
so that they are evenly spaced and don't overlap.  DO NOT
name the menu items "ArrangeIcons" as that will override
the TForm method.
} 
procedure TForm1.MyArrangeIconsClick(Sender: TObject);
begin
  Form1.ArrangeIcons;
end;

Copy Code

{
This example uses two edit boxes and one pop-up menu on a form.
The pop-up menu contains Cut, Copy, and Paste commands. This code
makes the pop-up menu available to both edit boxes:
} 
procedure TForm1.FormCreate(Sender: TObject);
begin
  PopupMenu1.AutoPopup := True;
  Edit1.PopupMenu := PopupMenu1;
  Edit2.PopupMenu := PopupMenu1;
end;

{
These are the cut, copy, and paste OnClick events for the commands
on the pop-up menu. Double click on the pop-up menu and add three
TMenuItems.  Then set the captions to "Cut", "Copy" and "Paste".
The names will be automatically set to "Cut1", "Copy1", and
"Paste1".  Then double click on the OnClick events and they will
be named "Cut1Click", "Copy1Click" and "Paste1Click" respectively.
Note: only the selected portion of the string in the edit box will
be copied, cut or replaced.
}
procedure TForm1.Copy1Click(Sender: TObject);
begin
  if PopupMenu1.PopupComponent = Edit1 then
   Edit1.CopyToClipboard
  else if PopupMenu1.PopupComponent = Edit2 then
    Edit2.CopyToClipboard
  else
    Beep;
end;

procedure TForm1.Cut1Click(Sender: TObject);
begin
  if PopupMenu1.PopupComponent = Edit1 then
    Edit1.CutToClipboard
  else if PopupMenu1.PopupComponent = Edit2 then
    Edit2.CutToClipboard
  else
    Beep;
end;

procedure TForm1.Paste1Click(Sender: TObject);
begin
  if PopupMenu1.PopupComponent = Edit1 then
    Edit1.PasteFromClipboard
  else if PopupMenu1.PopupComponent = Edit2 then
    Edit2.PasteFromClipboard
  else
    Beep;
end;

Copy Code

{
This example demonstrates how to add and delete menu items
to a popup menu at runtime and assign an event handler to
the OnClick event.  Place a TPopupMenu and three buttons on
the form named "AddButton", "EditButton",  and
"DestroyButton" and add OnClick events to all three buttons.
Put the TPopupMenu in the PopupMenu property of the form.
Place the PopupMenuItemsClick procedure in the TForm1 type
declaration so that it can be used as the method call for
the menu item OnClick event.
}

type
  TForm1 = class(TForm)
    AddButton: TButton;
    EditButton: TButton;
    DestroyButton: TButton;
    PopupMenu1: TPopupMenu;
    procedure AddButtonClick(Sender: TObject);
    procedure EditButtonClick(Sender: TObject);
    procedure DestroyButtonClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    procedure PopupMenuItemsClick(Sender: TObject);

  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.AddButtonClick(Sender: TObject);
var
  index: Integer;
  NewItem: TMenuItem;
begin
    // The owner (PopupMenu1) will cleanup this menu item.
  NewItem := TMenuItem.Create(PopupMenu1); // create the new item
  index := PopupMenu1.Items.Count;
  PopupMenu1.Items.Add(NewItem);// add it to the Popupmenu
  NewItem.Caption := 'Menu Item ' + IntToStr(index);
  NewItem.Tag := index;
  NewItem.OnClick :=
    PopupMenuItemsClick; // assign it an event handler
end;

procedure TForm1.PopupMenuItemsClick(Sender: TObject);
begin
  with Sender as TMenuItem do
  begin
    case Tag of
      0:  ShowMessage('first item clicked');
      1:  ShowMessage('second item clicked');
      2:  ShowMessage('third item clicked');
      3:  ShowMessage('fourth item clicked');
    end;
  end;
end;

{
To edit or destroy an item, grab its pointer via the Items
property.
}
procedure TForm1.EditButtonClick(Sender: TObject);
var
  ItemToEdit: TMenuItem;
begin
  ItemToEdit := PopupMenu.Items[1];
  ItemToEdit.Caption := 'Changed Caption';
end;

procedure TForm1.DestroyButtonClick(Sender: TObject);
var
  ItemToDelete: TMenuItem;
begin
  ItemToDelete := PopupMenu.Items[2];
  ItemToDelete.Free;
end;

procedure TForm1.FormCreate(Sender: TObject);
var
  index: Integer;
  NewItem: TMenuItem;
begin
  for index := 0 to 3 do
  begin
      // The owner (PopupMenu1) will cleanup this menu item.
    NewItem := TMenuItem.Create(PopupMenu1); // create the new item
    PopupMenu1.Items.Add(NewItem);// add it to the Popupmenu
    NewItem.Caption := 'Menu Item ' + IntToStr(index);
    NewItem.Tag := index;
    NewItem.OnClick :=
      PopupMenuItemsClick; // assign it an event handler
  end;
end;