初识 ATL COM 组件 ——一个简单的不含窗口的 VC 组件

主要用于了解一个COM 组件的开发过程和调用方式。

参考：
 
  http://www.cppblog.com/woaidongmao/archive/2011/01/10/138250.html


还有以下几个问题以后有时间、兴趣的话再来解决。
TODO： 1. 如何使用 ATL 开发一个带界面（比如文本输入）。
      （PS：VC的自动生成代码太多了，都有点晕了）
       2. 开发一个 MFC ActiveX 控件。
       3. 分别使用 VC，VB调用上述两个含窗口界面的控件/组件。
FIXME： 下面的示例中，VB调用该COM组件时，只读字符串属性 MyTxt 返回值不正确，VC调用却木问题。


 MyAtlCom.zip  


VC 开发的 COM组件 实现文件：

MyText.cpp

// MyText.cpp : Implementation of CMyText
#include "stdafx.h"
#include "MyAtlCom.h"
#include "MyText.h"

/////////////////////////////////////////////////////////////////////////////
// CMyText

long _MyNum = 0;
char * _MyTxt = "Hi~~";

STDMETHODIMP CMyText::MyAdd(long Num1, long Num2, long *ReturnVal)
{
    // TODO: Add your implementation code here
    *ReturnVal = Num1 + Num2;
    return S_OK;
}

STDMETHODIMP CMyText::get_MyNum(long *pVal)
{
    // TODO: Add your implementation code here
    *pVal = _MyNum;
    return S_OK;
}

STDMETHODIMP CMyText::put_MyNum(long newVal)
{
    // TODO: Add your implementation code here
    _MyNum = newVal;
    return S_OK;
}

STDMETHODIMP CMyText::get_MyTxt(BSTR *pVal)
{
    // TODO: Add your implementation code here
    *pVal = CComBSTR(_MyTxt);
    return S_OK;
}

======================================Client

VC 的命令行 Client

MAIN.CPP

#include <iostream.h>
#include <atlbase.h>
#import "MyAtlCom.dll" no_namespace
//using namespace MYATLCOMLib;




void main(void) {

    const IID IID_IMyText = {0x2C197EE8,0xA71C,0x4545,{0xB6,0x13,0xE5,0xE3,0xA5,0xAF,0x36,0x4C}};
    const IID LIBID_MYATLCOMLib = {0x15AC74AB,0x7178,0x4CF5,{0xAD,0x7A,0xED,0x9B,0xD4,0x91,0x93,0xED}};
    const CLSID CLSID_MyText = {0x5BDB5A8F,0xED08,0x4AD7,{0xB5,0x52,0x24,0xF3,0xF3,0xDE,0x81,0x76}};

    HRESULT            hr;
    // IMyText* i = NULL;

    hr = CoInitialize(NULL);
    if(SUCCEEDED(hr)){
        CComPtr<IMyText> p ;
        hr = p.CoCreateInstance( CLSID_MyText);
        if(SUCCEEDED(hr)) {
            long ReturnValue;
            hr = p->MyAdd(5, 7, &ReturnValue);
            cout << "The answer for 5 + 7 is: " << ReturnValue << endl;

            cout <<"MyNum = "<<p->GetMyNum()<< endl;
            p->PutMyNum(333);
            cout <<"MyNum = "<<p->GetMyNum()<< endl;

            cout <<"MyTxt = "<<p->GetMyTxt()<< endl;

        } else {
            cout << "CoCreateInstance Failed." << endl;
        }
    }
    CoUninitialize();
}

------------- VB Client

Form1.frm

VERSION 5.00
Begin VB.Form Form1
   Caption         =   "Form1"
   ClientHeight    =   3090
   ClientLeft      =   60
   ClientTop       =   450
   ClientWidth     =   4680
   LinkTopic       =   "Form1"
   ScaleHeight     =   3090
   ScaleWidth      =   4680
   StartUpPosition =   3  'Windows Default
   Begin VB.CommandButton Command1
      Caption         =   "Command1"
      Height          =   735
      Left            =   1440
      TabIndex        =   0
      Top             =   720
      Width           =   1575
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Private Sub Command1_Click()
    Dim m As MYATLCOMLib.MyText
    Set m = New MyText
    Dim l As Long

    m.MyAdd 1, 2, l
    MsgBox "MyAdd(1,2) = " & l

    Dim s As String
    s = m.MyTxt
    MsgBox "MyTxt = " & m.MyTxt 'FIXME wrong, 应该是 "Hi~~", 实际是 "MyTx"


    MsgBox " myNum = " & m.MyNum
    m.MyNum = 333
    MsgBox " myNum = " & m.MyNum
End Sub