yourpaseditcw.dpr

Object pascal源码,是个非常容易掌握的语法文件。

program YourPasEditcw;

uses Dialogs,
  Forms,
  Windows,
  SysUtils,
  About in 'About.pas' {frmAbout},
  YrPasEdit in 'YrPasEdit.pas' {frmYourPasEdit};

{$R *.RES}
var
  Previous: HWND;
  {This code, to allow file association and open doubleclicked file in the running instance of app
    	was written by Andrius Adamonis}
function EnumWindowsCallback(Handle: HWND; Param: LPARAM): Boolean; stdcall;
  function IsMyClass: Boolean;
  var
    ClassName    : array[0..30] of Char;
    FormClassName: string;              
  begin
    GetClassName(Handle, ClassName, 30);
    Result := (StrIComp(ClassName, 'TfrmYourPasEdit') = 0) and { this finds my window, TfrmYourPasEdit }
    (SendMessage(Handle, WM_FINDINSTANCE, 0, 0) = MyUniqueConst); { this checks if this is really my application }
  end;
begin
  Result := not IsMyClass; { needs True to continue }
  if not Result { = MyClass } then Previous := Handle;
end;

var
  ATOM: TAtom;
  
begin
  Previous := 0;
  ATOM := 0;
  EnumWindows(@EnumWindowsCallback, 0);
  if Previous <> 0 then
  begin
    PostMessage(Previous, WM_RESTOREAPP, 0, 0);
    if (ParamCount > 0) then
    begin
      ATOM := GlobalAddAtom(PChar(ParamStr(1)));
      SendMessage(Previous, WM_OPENEDITOR, ATOM, 0);
      GlobalDeleteAtom(ATOM);
    end;
    Exit;
  end;
  Application.Initialize;
  Application.Title := 'YourPasEdit';
  Application.CreateForm(TfrmYourPasEdit, frmYourPasEdit);
  if ParamCount > 0 then frmYourPasEdit.OpenFile(ParamStr(1));
  Application.Run;
end.