在窗口标题区添加按钮




 

ReadBook是一款优秀的软件，我相信读者中也有不少人在使用它。今天，我想给大家谈谈它是如何在窗口的标题区添加按钮的。有可能我的实现方法和ReadBook的不一样，没关系，大家互相学习吧！ 
　　程序主要用到了几个消息，除了程序中消息函数定义的方法外，大家还要注意每一个消息函数中都调用了inherited，原因不用我饶舌了吧？程序中还调用了GetSystemMetrics、DrawButtonFace等几个函数。我本来在程序中详细地加了注释，不过我后来都删除了，因为Delphi的帮助文件可以说是最好的注释了。如果你有什么不懂之处，别忘了按“F1”键，怎么样，一切都写得清清楚楚的吧？ 
　　把下边的程序输进计算机，自己用帮助文件研究吧。记住，学习编程可不能偷懒哦

unit Unit1; 

inte易做图ce 

uses 

Windows, Buttons, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs; 

type 

TForm1 = class(TForm) 

procedure FormResize(Sender: TObject); 

private 

{ Private declarations } 

CaptionBtn:TRect; 

procedure DrawCaptButton; 

rocedure WMNCPaint(var Msg:TWMNCPaint);message WM_NCPaint; 

procedure WMNCActivate(var Msg:TWMNCActivate);message WM_NCActivate; 

procedure WMSetText(var Msg:TWMSetText);message WM_SetText; 

procedure WMNCHitTest(var Msg:TWMNCHitTest);message WM_NCHittest; 

procedure WMNCLButtonDown(var Msg:TWMNCLButtonDown);message WM_NCLButtonDown; 

public 

{ Public declarations } 

end; 

var 

Form1: TForm1; 

implementation 

const 

htCaptionBtn=htSizeLast+1; 

{$R *.DFM} 

procedure TForm1.DrawCaptButton; 

var 

xFrame,yFrame,xSize,ySize:Integer; 

R:TRect; 

begin 

xFrame:=GetSystemMetrics(SM_CXFRAME); 

yFrame:=GetSystemMetrics(SM_CYFRAME); 

xSize:=GetSystemMetrics(SM_CXSIZE); 

ySize:=GetSystemMetrics(SM_CYSIZE); 

CaptionBtn:=Bounds(Width-xFrame-4*xSize+2,yFrame+2,xSize+1,ySize-4); 

Canvas.Handle:=GetWindowDC(Self.Handle); 

Canvas.Font.Name:=宋体; 

Canvas.Font.Color:=clBlack; 

Canvas.Pen.Color:=clYellow; 

Canvas.Brush.Color:=clBtnFace; 

try 

DrawButtonFace(Canvas,CaptionBtn,1,bsAutoDetect,False,False,False); 

R:=Bounds(Width-xFrame-4*xSize+3,yFrame+3,xSize-2,ySize-7); 

with CaptionBtn do 

Canvas.TextRect(R,R.Left+2,R.Top+2,?); 

finally 

ReleaseDC(Self.Handle,Canvas.Handle); 

Canvas.Handle:=0; 

end; 

end;

procedure TForm1.WMNCActivate(var Msg: TWMNCActivate); 

begin 

inherited; 

DrawCaptButton; 

end; 

procedure TForm1.WMNCHitTest(var Msg: TWMNCHitTest); 

begin 

inherited; 

with Msg do 

if PtInRect(CaptionBtn,Point(xPos-Left,yPos-Top)) then 

Result:=htCaptionBtn; 

end; 

procedure TForm1.WMNCLButtonDown(var Msg: TWMNCLButtonDown); 

begin 

inherited; 

if(Msg.HitTest=htCaptionBtn)then 

showmessage(成功了!); 

end; 

procedure TForm1.WMNCPaint(var Msg: TWMNCPaint); 

begin 

inherited; 

DrawCaptButton; 

end; 

procedure TForm1.WMSetText(var Msg: TWMSetText); 

begin 

inherited; 

DrawCaptButton; 

end; 

procedure TForm1.FormResize(Sender: TObject); 

begin 

Perform(WM_NCACTIVATE,Word(Active),0); 

end; 

end. 

　　仔细研究一下程序中有关计算的几个句子，试着改变某个数字看一看，这将有助于你理解程序。