怎样为控件增加事件？

Question

比如一个控件什么事件都没有,怎样增加？举个例子.

Answer 1

procedure TForm1.MyClick(Sender: TObject);
begin
  .........  
end;procedure TForm1.FormCreate(Sender: TObject);
begin
  Button1.OnClick := MyClick;
end;

Answer 2

下例是为dbgrid增加鼠标滚轮的事件代码（转贴）：///////////////
unit WJDBGrid;
//增加了3个功能
//1：鼠标滚轮相应；如果定义了ONCELLCLICK事件，那么在滚动时，自动调用此事件
//2：初始化时将READONLY赋为TRUE;
//3：如果DATASET为TCUSTOMADODATASET,则在单击行标题时，进行排序;
interfaceuses
  SysUtils, Classes, Controls, Grids, DBGrids, AdoDB;type
  TWJDBGrid = class(TDBGrid)
  private
    { Private declarations }
  protected
    { Protected declarations }
    procedure CMMouseWheel(var Message: TCMMouseWheel); message CM_MOUSEWHEEL;
  public
    { Public declarations }
    constructor Create(AOwner: TComponent); override;
    procedure TitleClick(Column:TColumn);
  published
    { Published declarations }
    //property OnMouseWheel;
  end;procedure Register;implementationprocedure Register;
begin
  RegisterComponents('Data Controls', [TWJDBGrid]);
end;{ TWJDBGrid }procedure TWJDBGrid.CMMouseWheel(var Message: TCMMouseWheel);
begin
    if Enabled then
    if Assigned(DataSource) and Assigned(DataSource.DataSet)
     and DataSource.DataSet.Active and (DataSource.DataSet.RecordCount>0) then
    begin
        if Message.WheelDelta<0 then
           DataSource.DataSet.Next;
        if Message.WheelDelta>0 then
            DataSource.DataSet.prior;
        if Assigned(OnCellClick) then
            OnCellClick(nil);
        message.Result:=1;
//这里要关闭 Inherited，否则会有上面所提及的问题
    end else
    begin
         Inherited;
    end;
end;constructor TWJDBGrid.Create(AOwner: TComponent);
begin
  inherited;
    Readonly:=true;
    OnTitleClick:=TitleClick;
end;procedure TWJDBGrid.TitleClick(Column: TColumn);
var i:integer;
    tem:string;
begin
    if Enabled then
    if Assigned(DataSource) and Assigned(DataSource.DataSet)
     and DataSource.DataSet.Active and (DataSource.DataSet.RecordCount>0) then
    begin
        if DataSource.DataSet is TCustomAdoDataSet then
            with DataSource.DataSet as TCustomAdoDataSet do
            begin
                tem:=Column.FieldName;
                if Sort='' then    
                    Sort:=tem+' ASC'
                else if Sort=tem+' ASC' then  
                    Sort:=tem+' DESC'
                else Sort:=tem+' ASC'; 
            end;
    end;
end;end.

Answer 3

type
TMyEvent=procedure(Sender:TObject;其他参数) of ObjectFMyEvent:TMyEvent;
property MyEvent:TMyEvent read FMyEvent write FMyEvent;
if Assigned(FMyEvent) then
    FMyEvent(Self,参数)

Answer 4

dulei115() ( ) 
同意