Delphi 怎么不注册 dll 就调用 com

一.方法
前言:
如果你的程序中使用了 COM对象或者 OCX控件,
发布程序的时候必须带上相关的 DLL文件或者 OCX文件,
同时还需要注册到系统中,
如果我想让我的程序 Copy & Run, 不需要安装,(现在流行绿色软件嘛)
那么使用下面的方法可以调用未注册的 COM对象或者 OCX控件

我仅仅提供简单的方法,大家共同研究,经验共享

如果COM对象没有在注册表中注册,那么按照下面的方法创建它

function CreateComObjectFromDll(CLSID: TGUID; DllHandle: THandle): IUnknown;
var
Factory: IClassFactory;
DllGetClassObject: function(const CLSID, IID: TGUID; var Obj): HResult;
stdcall;
begin
DllGetClassObject := GetProcAddress(DllHandle, 'DllGetClassObject');
if Assigned(DllGetClassObject) then
begin
DllGetClassObject(CLSID, IClassFactory, Factory);
Factory.CreateInstance(nil, IUnknown, Result);
end;
end;



二.例子

下面是用上面的函数从ocx 文件中创建对象的例子
此处创建了一个 MSCOMM32 的串口控件,
调用了此控件的 AboutBox 的对话框,

不管此ocx 文件是否已经注册到系统中,下面的程序都会正常执行

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ComObj, ActiveX;

type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
Button3: TButton;
Button4: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
private
{ Private declarations }
public
ocxhdl: THandle;
comm: Variant;
end;

const
CLASS_MSComm: TGUID = '{648A5600-2C6E-101B-82B6-000000000014}';


var
Form1: TForm1;

function CreateComObjectFromDll(CLSID: TGUID; DllHandle: THandle): IUnknown;

implementation

{$R *.dfm}

function CreateComObjectFromDll(CLSID: TGUID; DllHandle: THandle): IUnknown;
var
Factory: IClassFactory;
DllGetClassObject: function(const CLSID, IID: TGUID; var Obj): HResult;
stdcall;
begin
DllGetClassObject := GetProcAddress(DllHandle, 'DllGetClassObject');
if Assigned(DllGetClassObject) then
begin
DllGetClassObject(CLSID, IClassFactory, Factory);
Factory.CreateInstance(nil, IUnknown, Result);
end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
ocxhdl := LoadLibrary('mscomm32.ocx');
if ocxhdl < 32 then
ShowMessage('error');
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
comm := CreateComObjectFromDll(CLASS_MSComm, ocxhdl) as IDispatch;
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
comm.AboutBox;
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
comm := Null;
end;

end.