如何将一个事件作为函数参数传递？

Question

我有一个表单，它有我创建的有用过程的列表，我经常在每个项目中使用它。我添加了一个程序，可以简单地在可以点击的图像上添加一个TListBoxItem的TAccessory。该程序引入口列表框当前，但我也将它需要摄入量，以呼吁onclick事件图像该程序。这里是我的现有代码：

function ListBoxAddClick(ListBox:TListBox{assuming I need to add another parameter here!! but what????}):TListBox; 
var 
    i  : Integer; 
    Box  : TListBox; 
    BoxItem : TListBoxItem; 
    Click : TImage; 
begin 
    i := 0; 
    Box := ListBox; 
    while i <> Box.Items.Count do begin 
    BoxItem := Box.ListItems[0]; 
    BoxItem.Selectable := False; 

    Click := Timage.Create(nil); 
    Click.Parent := BoxItem; 
    Click.Height := BoxItem.Height; 
    Click.Width := 50; 
    Click.Align := TAlignLayout.alRight; 
    Click.TouchTargetExpansion.Left := -5; 
    Click.TouchTargetExpansion.Bottom := -5; 
    Click.TouchTargetExpansion.Right := -5; 
    Click.TouchTargetExpansion.Top := -5; 
    Click.OnClick := // this is where I need help 

    i := +1; 
    end; 
    Result := Box; 
end; 

所需的程序将在形式定义那就是调用这个函数。

Answer 1

由于OnClick事件类型为TNotifyEvent您应该定义该类型的参数。看看这个（我希望自我解释）例如：

type 
    TForm1 = class(TForm) 
    Button1: TButton; 
    ListBox1: TListBox; 
    procedure Button1Click(Sender: TObject); 
    private 
    procedure TheClickEvent(Sender: TObject); 
    end; 

implementation 

procedure ListBoxAddClick(ListBox: TListBox; OnClickMethod: TNotifyEvent); 
var 
    Image: TImage; 
begin 
    Image := TImage.Create(nil); 
    // here is assigned the passed event method to the OnClick event 
    Image.OnClick := OnClickMethod; 
end; 

procedure TForm1.Button1Click(Sender: TObject); 
begin 
    // here the TheClickEvent event method is passed 
    ListBoxAddClick(ListBox1, TheClickEvent); 
end; 

procedure TForm1.TheClickEvent(Sender: TObject); 
begin 
    // do something here 
end;