onecopy.dpr

Delphi7从入门到精通及附书源码 Delphi7从入门到精通及附书源码

program OneCopy;

uses
  Forms, Windows, Messages, SysUtils,
  OneF in 'OneF.pas' {Form1};

{$R *.RES}

var
  hMutex: THandle;
  FoundWnd: THandle;
  ModuleName: string;

function EnumWndProc (hwnd: THandle;
  Param: Cardinal): Bool; stdcall;
var
  ClassName, WinModuleName: string;
  WinInstance: THandle;
begin
  Result := True;
  SetLength (ClassName, 100);
  GetClassName (hwnd, PChar (ClassName), Length (ClassName));
  ClassName := PChar (ClassName);
  if ClassName = TForm1.ClassName then
  begin
    // get the module name of the target window
    SetLength (WinModuleName, 200);
    WinInstance := GetWindowLong (hwnd, GWL_HINSTANCE);
    GetModuleFileName (WinInstance,
      PChar (WinModuleName), Length (WinModuleName));
    WinModuleName := PChar(WinModuleName); // adjust length

    // compare module names
    if WinModuleName = ModuleName then
    begin
      FoundWnd := Hwnd;
      Result := False; // stop enumeration
    end;
  end;
end;

begin
  // check if mutex already exists
  HMutex := CreateMutex (nil, False, 'OneCopyMutex');
  if WaitForSingleObject (hMutex, 0) <> wait_TimeOut then
  begin
    Application.Initialize;
    Application.CreateForm(TForm1, Form1);
    Application.Run;
  end
  else
  begin
    // get the current module name
    SetLength (ModuleName, 200);
    GetModuleFileName (HInstance,
      PChar (ModuleName), Length (ModuleName));
    ModuleName := PChar (ModuleName); // adjust length

    // find window of previous instance
    EnumWindows (@EnumWndProc, 0);
    if FoundWnd <> 0 then
    begin
      // show the window, eventually
      if not IsWindowVisible (FoundWnd) then
        PostMessage (FoundWnd, wm_App, 0, 0);
      SetForegroundWindow (FoundWnd);
    end;
  end;
end.