实现控件的移动，改变大小（DELPHI实现）

主要使用Perform方法
  function Perform(Msg: Cardinal; WParam, LParam: Longint): Longint;
 
只要能够使用类似于win32API的函数SendMessage()，本方法同样可在其他环境里应用。

用Delphi实现
首先，建立一个应用程序，在一个窗体里加入一个Panel1，保存为main.pas；
然后，分别在Panel1的鼠标移动、鼠标按下事件里添加代码；
鼠标移动：控制光标的形状
procedure TForm1.Panel1MouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
begin
  if (x>=0)and(x<=3) then
  begin
    if (y>=0)and(y<=3) then Panel1.Cursor:=crSizeNWSE;
    if (y>3)and(y<Panel1.Height-3) then Panel1.Cursor:=crSizeWE;
    if (y>=Panel1.Height-3)and(y<=Panel1.Height) then Panel1.Cursor:=crSizeNESW;
  end
  else if (x>3)and(x<Panel1.Width-3) then
  begin
    if (y>=0)and(y<=3) then Panel1.Cursor:=crSizeNS;
    if (y>3)and(y<Panel1.Height-3) then Panel1.Cursor:=crArrow;
    if (y>=Panel1.Height-3)and(y<=Panel1.Width) then Panel1.Cursor:=crSizeNS;
  end
  else if (x>=Panel1.Width-3)and(x<=Panel1.Width) then
  begin
    if (y>=0)and(y<=3) then Panel1.Cursor:=crSizeNESW;
    if (y>3)and(y<Panel1.Height-3) then Panel1.Cursor:=crSizeWE;
    if (y>=Panel1.Height-3)and(y<=Panel1.Width) then Panel1.Cursor:=crSizeNWSE;
  end;
end;

鼠标按下：控制Panel的大小或位置
procedure TForm1.Panel1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  ReleaseCapture;
  if (x>=0)and(x<=3) then
  begin
    file://左上角方向改变大小
    if (y>=0)and(y<=3) then Panel1.Perform(WM_SysCommand,$F004,0);
    file://左侧
    if (y>3)and(y<Panel1.Height-3) then Panel1.Perform(WM_SysCommand,$F001,0);
    file://左下角
    if (y>=Panel1.Height-3)and(y<=Panel1.Height) then Panel1.Perform(WM_SysCommand,$F007,0);
  end
  else if (x>3)and(x<Panel1.Width-3) then
  begin
    file://上侧
    if (y>=0)and(y<=3) then Panel1.Perform(WM_SysCommand,$F003,0);
    file://移动控件
    if (y>3)and(y<Panel1.Height-3) then Panel1.Perform(WM_SysCommand,$F012,0);
    file://下侧
    if (y>=Panel1.Height-3)and(y<=Panel1.Width) then Panel1.Perform(WM_SysCommand,$F006,0);
  end
  else if (x>=Panel1.Width-3)and(x<=Panel1.Width) then
  begin
    file://右上角
    if (y>=0)and(y<=3) then Panel1.Perform(WM_SysCommand,$F005,0);
    file://右侧
    if (y>3)and(y<Panel1.Height-3) then Panel1.Perform(WM_SysCommand,$F002,0);
    file://右下角
    if (y>=Panel1.Height-3)and(y<=Panel1.Width) then Panel1.Perform(WM_SysCommand,$F008,0);
  end;
end;
主要使用 Perform 方法为

附录1.全部代码如下：

unit main;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    Panel1: TPanel;
    procedure Panel1MouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure Panel1MouseMove(Sender: TObject; Shift: TShiftState; X,
      Y: Integer);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.Panel1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  ReleaseCapture;
  if (x>=0)and(x<=3) then
  begin
    if (y>=0)and(y<=3) then Panel1.Perform(WM_SysCommand,$F004,0);
    if (y>3)and(y<Panel1.Height-3) then Panel1.Perform(WM_SysCommand,$F001,0);
    if (y>=Panel1.Height-3)and(y<=Panel1.Height) then Panel1.Perform(WM_SysCommand,$F007,0);
  end
  else if (x>3)and(x<Panel1.Width-3) then
  begin
    if (y>=0)and(y<=3) then Panel1.Perform(WM_SysCommand,$F003,0);
    if (y>3)and(y<Panel1.Height-3) then Panel1.Perform(WM_SysCommand,$F012,0);
    if (y>=Panel1.Height-3)and(y<=Panel1.Width) then Panel1.Perform(WM_SysCommand,$F006,0);
  end
  else if (x>=Panel1.Width-3)and(x<=Panel1.Width) then
  begin
    if (y>=0)and(y<=3) then Panel1.Perform(WM_SysCommand,$F005,0);
    if (y>3)and(y<Panel1.Height-3) then Panel1.Perform(WM_SysCommand,$F002,0);
    if (y>=Panel1.Height-3)and(y<=Panel1.Width) then Panel1.Perform(WM_SysCommand,$F008,0);
  end;
end;

procedure TForm1.Panel1MouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
begin
  if (x>=0)and(x<=3) then
  begin
    if (y>=0)and(y<=3) then Panel1.Cursor:=crSizeNWSE;
    if (y>3)and(y<Panel1.Height-3) then Panel1.Cursor:=crSizeWE;
    if (y>=Panel1.Height-3)and(y<=Panel1.Height) then Panel1.Cursor:=crSizeNESW;
  end
  else if (x>3)and(x<Panel1.Width-3) then
  begin
    if (y>=0)and(y<=3) then Panel1.Cursor:=crSizeNS;
    if (y>3)and(y<Panel1.Height-3) then Panel1.Cursor:=crArrow;
    if (y>=Panel1.Height-3)and(y<=Panel1.Width) then Panel1.Cursor:=crSizeNS;
  end
  else if (x>=Panel1.Width-3)and(x<=Panel1.Width) then
  begin
    if (y>=0)and(y<=3) then Panel1.Cursor:=crSizeNESW;
    if (y>3)and(y<Panel1.Height-3) then Panel1.Cursor:=crSizeWE;
    if (y>=Panel1.Height-3)and(y<=Panel1.Width) then Panel1.Cursor:=crSizeNWSE;
  end;
end;

附录2.API SendMessage()介绍
SendMessage === user32.lib
LRESULT SendMessage(

    HWND hWnd, // handle of destination window
    UINT Msg, // message to send
    WPARAM wParam, // first message parameter
    LPARAM lParam  // second message parameter
   );

             2001.9.27