这里是Perform方法的源代码
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function TControl.Perform(Msg: Cardinal; WParam, LParam: Longint): Longint;
var
Message: TMessage;//定义消息为TMessage结构
begin
Message.Msg := Msg;//填入你的消息标识到TMessage的Msg域
Message.WParam := WParam;
Message.LParam := LParam;//参数与TMessage消息参数一样，说明Perform还是将消息翻译为TMessage来处理的
Message.Result := 0;//返回值为0，即没有处理
if Self <> nil then WindowProc(Message);//这里是关键！将消息交给TControl的窗口过程（WindowProc）处理
Result := Message.Result;
end;
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property WindowProc: TWndMethod read FWindowProc write FWindowProc;
//这里说明了WindowProc作为TControl的一个属性，依靠TWndMethod类型的变量FWindowProc来读写
constructor TControl.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
FWindowProc := WndProc;
....
//这里说明在组件创建的时候将WndProc写入变量FWindowProc 中
procedure WndProc(var Message: TMessage); virtual;
//这里说明WndProc(var Message: TMessage)方法是个虚拟的方法，可以自己重载！
TWinControl = class(TControl)
..
procedure WndProc(var Message: TMessage);Override;//在TWinControl重载TControl的同名方法
下面就是追到的处理部分了
TControl的处理部分
procedure TControl.WndProc(var Message: TMessage);
var
Form: TCustomForm;
KeyState: TKeyboardState;
WheelMsg: TCMMouseWheel;
begin
if (csDesigning in ComponentState) then
begin
Form := GetParentForm(Self);
if (Form <> nil) and (Form.Designer <> nil) and
Form.Designer.IsDesignMsg(Self, Message) then Exit
end;
if (Message.Msg >= WM_KEYFIRST) and (Message.Msg <= WM_KEYLAST) then
begin
Form := GetParentForm(Self);
if (Form <> nil) and Form.WantChildKey(Self, Message) then Exit;
end
else if (Message.Msg >= WM_MOUSEFIRST) and (Message.Msg <= WM_MOUSELAST) then
begin
if not (csDoubleClicks in ControlStyle) then
case Message.Msg of
WM_LBUTTONDBLCLK, WM_RBUTTONDBLCLK, WM_MBUTTONDBLCLK:
Dec(Message.Msg, WM_LBUTTONDBLCLK - WM_LBUTTONDOWN);
end;
case Message.Msg of
WM_MOUSEMOVE: Application.HintMouseMessage(Self, Message);
WM_LBUTTONDOWN, WM_LBUTTONDBLCLK:
begin
if FDragMode = dmAutomatic then
begin
BeginAutoDrag;//拖放
Exit;
end;
Include(FControlState, csLButtonDown);
end;
WM_LBUTTONUP:
Exclude(FControlState, csLButtonDown);
else
with Mouse do
if WheelPresent and (RegWheelMessage <> 0) and
(Message.Msg = RegWheelMessage) then
begin
GetKeyboardState(KeyState);
with WheelMsg do
begin
Msg := Message.Msg;
ShiftState := KeyboardStateToShiftState(KeyState);
WheelDelta := Message.WParam;
Pos := TSmallPoint(Message.LParam);
end;
MouseWheelHandler(TMessage(WheelMsg));
Exit;
end;
end;
end
else if Message.Msg = CM_VISIBLECHANGED then
with Message do
SendDockNotification(Msg, WParam, LParam);
Dispatch(Message);//发送消息
end;
TWinControl重载后新加的处理部分
procedure TWinControl.WndProc(var Message: TMessage);
var
Form: TCustomForm;
begin
case Message.Msg of
WM_SETFOCUS:
begin
Form := GetParentForm(Self);
if (Form <> nil) and not Form.SetFocusedControl(Self) then Exit;
end;
WM_KILLFOCUS:
if csFocusing in ControlState then Exit;
WM_NCHITTEST:
begin
inherited WndProc(Message);//先重载父类的方法
if (Message.Result = HTTRANSPARENT) and (ControlAtPos(ScreenToClient(
SmallPointToPoint(TWMNCHitTest(Message).Pos)), False) <> nil) then
Message.Result := HTCLIENT;
Exit;
end;
WM_MOUSEFIRST..WM_MOUSELAST:
if IsControlMouseMsg(TWMMouse(Message)) then
begin
{ Check HandleAllocated because IsControlMouseMsg might have freed the
window if user code executed something like Parent := nil. }
if (Message.Result = 0) and HandleAllocated then
DefWindowProc(Handle, Message.Msg, Message.wParam, Message.lParam);
Exit;
end;
WM_KEYFIRST..WM_KEYLAST:
if Dragging then Exit;
WM_CANCELMODE:
if (GetCapture = Handle) and (CaptureControl <> nil) and
(CaptureControl.Parent = Self) then
CaptureControl.Perform(WM_CANCELMODE, 0, 0);
end;
inherited WndProc(Message);
end;
关键的都在这里了，你自己去看看吧
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这些代码都是Controls.pas单元中的，位置在X:/../Borland/Delphi6/Source/Vcl中
的Controls文件。自己找，看看对你消化消息处理由很大作用的！
