我想自定意消息却不知怎样做呀急呀

Question

WNDPROC重载怎样用呀请各位高手给具体介绍或者给一个简单的小例子在此感谢了呀

Answer 1

unit Unit4;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;type
  TForm4 = class(TForm)
    ListBox1: TListBox;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  protected
    procedure Wndproc (var message:Tmessage);override;
  end;var
  Form4: TForm4;implementation
uses shellapi;{$R *.dfm}
procedure TForm4.Wndproc(var message: Tmessage);
var
  Count, Index,hDrop:Integer;
  PFileName:PChar;
begin
  if message.Msg = WM_DROPFILES then
  begin
    hDrop :=message.WParam;
    GetMem(PFileName,MAX_PATH);
    Count :=DragQueryFile(hDrop, MAXDWORD, PFileName, MAX_PATH-1);
    ListBox1.Items.Clear;
    for Index :=0 to Count-1 do
    begin
      DragQueryFile(hDrop, Index, PFileName, MAXBYTE);
      ListBox1.Items.Add(PFileName);
    end;
    FreeMem(PFileName);
    DragFinish(hdrop);
  end else
  begin
    inherited;
  end;
end;
procedure TForm4.FormCreate(Sender: TObject);
begin
  DragAcceptFiles(Handle, true);
end;procedure TForm4.FormDestroy(Sender: TObject);
begin
  DragAcceptFiles(Handle, false);
end;end.