VC下的ADO編程入門(1)

n          新建一基於對話框的應用程序zjy，在對話框上添加一個列表框和一個按鈕，用ClassWizard給列表框添加一個變量m_list

n          在StdAfx.h頭文件的所有include語句下面添加如下一條語句

#import "c:program filescommon filessystemadomsado15.dll" no_namespace rename ("EOF","adoEOF")

n          在zjyDlg.h頭文件處添加兩個變量

         _ConnectionPtr m_pConnection;

         _RecordsetPtr m_pRecordset;

n          在zjyDlg.cpp的BOOL CZjyDlg::OnInitDialog()的return TRUE;語句前添加如下語句

         if(!AfxOleInit())

         {

                   AfxMessageBox("COM Error!");                 

         }

n          添加按鈕的消息響應函數並寫入下面代碼

void CZjyDlg::OnButton1()

{

         m_list.ResetContent();

         int i=0;

         m_pConnection.CreateInstance(__uuidof(Connection));

         m_pRecordset.CreateInstance(__uuidof(Recordset));

         try{

                   m_pConnection->Open("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=E:\ActiveX 數據對象\VC_Access\zjy\MyDb1.mdb;","","",0);

                   m_pRecordset->Open("SELECT * FROM MyTable1",(IDispatch *)m_pConnection,adOpenDynamic,adLockOptimistic,adCmdText);

                   m_pRecordset->MoveFirst();

                   while(!m_pRecordset->adoEOF)

                   {

                            i=i+1;

                            _variant_t theValue = m_pRecordset->GetCollect("n1");

                            if(theValue.vt != VT_NULL)

                                     m_list.AddString((char *)_bstr_t(theValue));

                            m_pRecordset->MoveNext();

                   }

                   m_pRecordset->Close();

                   m_pConnection->Close();

         }

         catch(_com_error e)

         {

                   AfxMessageBox(e.ErrorMessage());

         } 

         char str[32];

         sprintf(str,"table have %d record",i);

         AfxMessageBox(str);

         m_pRecordset = NULL;

         m_pConnection = NULL;

}

完成的功能就是把Access數據庫中的某表的某一字段添加到列表框中。下一篇介紹把SQL Server數據庫中的某表添加到列表視圖中。