学步园

//初始化数据库连接
::CoInitialize(NULL);

BOOL CLogin::ConnectDB(void)
{
	HRESULT hr = NULL;
	try 
	{
		hr = m_pConnection.CreateInstance("ADODB.Connection");///创建 Connection 对象 
 
		if(SUCCEEDED(hr))   
		{
			//登录数据库并连接数据库DBCourse
			//这里的server不能写成127.0.0.1否则会出现未指定的错误，应该写成Sql server登录界面的服务器名称
			m_pConnection->ConnectionString = "driver={SQL Server};server=LOGO-PC\\LOGO;uid=DBCourse;pwd=DBCourse;";
			m_pConnection->Open("","","",adConnectUnspecified);
			m_pConnection->DefaultDatabase = "DBCourse";
		}
		else
		{
			AfxMessageBox(TEXT("创建 Connection 对象失败"));///显示错误信息
			return FALSE;
		}
	}   
	catch(_com_error e)///捕捉异常   
	{ 
		CString errormessage;
		errormessage.Format( TEXT("连接数据库失败 !\r\n 错误信息 :%s(%ld)"),e.ErrorMessage(),e.Error() ); 
		AfxMessageBox(errormessage);///显示错误信息  
		return FALSE;
	}
	return TRUE;
}

void CLogin::OnBnClickedButton1()
{
	if( m_user.GetWindowTextLength()<=0 || m_password.GetWindowTextLength()<=0 )
	{
		MessageBox(TEXT("请输入用户名或密码！"), TEXT("错误:用户名或密码为空"), MB_OK | MB_ICONWARNING );
		return;
	}
	if( FALSE==this->ConnectDB() ) return;

	TCHAR szUserName[20];
	TCHAR szPassword[50];
	TCHAR szSql[MAX_PATH];
	
	//获取用户输入的用户名和密码
	m_user.GetWindowText( szUserName, 20 );
	m_password.GetWindowText( szPassword, 50 );

	//创建_RecordsetPtr用来执行数据库操作
	_RecordsetPtr pRecordset;
	pRecordset.CreateInstance("ADODB.Recordset");

	_tcscpy_s( szSql, TEXT("select * from usr where uname='") );
	_tcscat_s( szSql, szUserName );
	_tcscat_s( szSql, TEXT("' and passwd='") );
	_tcscat_s( szSql, szPassword );
	_tcscat_s( szSql, TEXT("';") );
	pRecordset->Open(_variant_t(szSql),  _variant_t  ((IDispatch*) m_pConnection,true), adOpenStatic, adLockOptimistic, adCmdText);
	
	int nResult = DLG_RESULT_OK;
	if( pRecordset->RecordCount>0 )
	{
		//MessageBox(TEXT("登录成功！"), szUserName, MB_OK | MB_ICONINFORMATION );
	}
	else
	{
		MessageBox(TEXT("用户名或密码错误！"), TEXT("登录失败！"), MB_OK | MB_ICONINFORMATION );
		nResult = DLG_RESULT_ERROR;
	}
	pRecordset->Close();
	if( DLG_RESULT_OK==nResult ) Exit( DLG_RESULT_OK );
}

//添加dll库
#import "c:\program files\common files\system\ado\msado15.dll" no_namespace rename("EOF","adoEOF") 
//添加dll库

//添加宏定义
#define DLG_RESULT_OK     1
#define DLG_RESULT_ERROR  2
#define DLG_RESULT_CANCEL 3
//添加宏定义

即可！