实现控件的移动、改变大小（DELPHI实现）[1]

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