程序代码：

#include <stdio.h> 
#include <windows.h>
#include <string.h>

#import "c:\Program Files\Common Files\System\ado\msado15.dll" no_namespace rename("EOF","adoEOF")   //引入ADO库

int main(void)
{
    _ConnectionPtr m_pConnection=NULL;
    CoInitialize(NULL);  //初始化com库
    HRESULT hr = m_pConnection.CreateInstance("ADODB.Connection");    //创建Connection对象
    if(SUCCEEDED(hr))  //创建数据库connection对象成功
    {
        hr = m_pConnection->Open("Driver={Microsoft dBase Driver (*.dbf)}","","",adModeUnknown);
        if(SUCCEEDED(hr))   //连接数据库字符串成功
        {
            _RecordsetPtr MySet;
            MySet.CreateInstance(__uuidof(Recordset));
            MySet->Open("SELECT * FROM 123",m_pConnection.GetInterfacePtr(),adOpenDynamic,adLockOptimistic,adCmdText);
            _variant_t Holder;
            while(!MySet->adoEOF)
            {
                Holder = MySet->GetCollect("XMMC");
                if(Holder.vt!=VT_NULL)
                    printf("%s\n",(char*)_bstr_t(Holder));
                MySet->MoveNext();
            }

        }
    }
    return 0;
}

程序代码：

#include<iostream>
#include<string>
using namespace std;

#import "c:\Program Files\Common Files\System\ado\msado15.dll" no_namespace rename("EOF","adoEOF") rename("BOF","adoBOF")

class ADOConn
{
    //定义变量
public:
    _ConnectionPtr m_pConnection;//添加一个纸箱Connection对象的指针
    _RecordsetPtr m_pRecordset;//添加一个指向Recordset对象的指针
    //定义方法
public:
    ADOConn(){};
    virtual ~ADOConn(){};
    void OnInitADOConn();//初始化——连接数据库
    _RecordsetPtr& GetRecordSet(_bstr_t bstrSQL);//执行查询
    BOOL ExecuteSQL(_bstr_t bstrSQL);//执行sql语句，Insert Update_variant_t
    void ExitConnect();
};

void  ADOConn::OnInitADOConn()
{
    //初始化OLE/COM库环境
    ::CoInitialize(NULL);

    //创建Connection对象
    m_pConnection.CreateInstance("ADODB.Recordset");
    //设置连接字符串，必须是BSTR型或_bstr_t类型

    _bstr_t strConnect = "Provider=SQLOLEDB;Server=我的计算机;Database=Student;uid=sa;pwd=123456";

    
    /**********************************************************************************************/
    //                                 调试时在此处出错
    /**********************************************************************************************/
    m_pConnection->Open(strConnect, "", "", adModeUnknown);

    /**********************************************************************************************/
}

_RecordsetPtr& ADOConn::GetRecordSet(_bstr_t bstrSQL)
{
    //连接数据库，如果Connection对象为空，则重新连接数据库
    if (m_pConnection == NULL)
        OnInitADOConn();
    //创建记录集对象
    m_pRecordset.CreateInstance(__uuidof(Recordset));
    //取得表中记录
    m_pRecordset->Open(bstrSQL, m_pConnection.GetInterfacePtr(), adOpenDynamic, adLockOptimistic, adCmdText);

    return m_pRecordset;//返回记录集
}

//BOOL ADOConn::ExecuteSQL(_bstr_t bstrSQL)
//{
//    try
//    {
//        //是否已经连接数据库
//        if (m_pConnection == NULL)
//            OnInitADOConn();
//        m_pConnection->Execute(bstrSQL, NULL, adCmdText);
//
//        return true;
//    }
//    catch (_com_error e)
//    {
//        return false;
//    }
//}
//
//void ADOConn::ExitConnect()
//{    //关闭记录集和连接
//    if (m_pRecordset != NULL)
//        m_pRecordset->Close();
//    m_pConnection->Close();
//
//    ::CoUninitialize();//释放环境
//}

void main()
{
    string Sname;
    ADOConn m_AdoConn;
    m_AdoConn.OnInitADOConn();
    //设置select语句
    _bstr_t vSQL;
    vSQL = "select sname from Student";
    _RecordsetPtr m_pRecordset;
    m_pRecordset = m_AdoConn.GetRecordSet(vSQL);
    Sname = (LPCTSTR)(_bstr_t)m_pRecordset->GetCollect("sname");
    cout << Sname;
}

[此贴子已经被作者于2015-12-21 09:51编辑过]