VC中如何正确使用ADO？

[BluePenguin]

我用VC已经能通过ADO访问ACCESS数据库的表了，但我从表中得到的中文字段却无法正常显示。下面是我使用的代码：
pRs->MoveFirst();
pField=pRs->Fields->GetItem("课程名称");
BSTR name;
pField->get_Name(&name);
MessageBox((const char*)name);

[zhq2000]

试试这个

variant_t name;
pFild->get_Name(&name);
CString str((BSTR)name);
MessageBox(str);

[zhq2000]

sorry! 上面的 variant_t name 应为 _variant_t name;
_bstr_t name;
pField->get_Name(&name);
CString str((BSTR)name);

[Edward]

老天，中文子短命呀！
不过你的程序明显有问题：
BSTR 不能直接强制转换成 const char *；BSTR 的用法相当于 LPWSTR（wchar_t *），只不过需要特殊的 APIs 来操作罢了。
MessageBox((const char*)name); 此句 99.99% 的情况下得不到正确结果！
你没忘记 ::SysFreeString(name) 吧？
另外，直接用 VC 给你自动生成的高级包装类功能起步更好，开发速度更快（当然，性能有所损失）？
_variant_t varName;

varName = pField->name;
MessageBox(varName); //_MBCS, _UNICODE 都没问题！

@C msdn 有关帮助。

[Edward]

Sorry, the last line in my reply above should read:
MessageBox((_bstr_t)varName); //_MBCS, _UNICODE 都没问题！

Another type coercion is safer:
MessageBox((LPCTSTR)(_bstr_t)varName); //_MBCS, _UNICODE 都没问题！

[halbert]

关于vc++ 的ado 编程
atdafx.h
#import "c:\program files\common files\system\ado\msado15.dll" no_namespace rename ("EOF", "adoEOF")

BOOL CGetemailApp::InitInstance()
{
// Initialize OLE libraries
if (!AfxOleInit())
{
AfxMessageBox("ole 出错");
return FALSE;
}
::CoInitialize( NULL );
}
int CGetemailApp::ExitInstance()
{
// TODO: Add your specialized code here and/or call the base class
::CoUninitialize();
return CWinApp::ExitInstance();
}

bool getrecordset()
{
char SqlStr[255],account[50];
char Error[500];
char putfilestr[300];
long recordnum;
m_pConnection = NULL;
m_pRecordset = NULL;
_variant_t TheEmail,ThePhone_office,TheAccount,TheUser_id;
char strEmail[50],strPhone_offiece[50],strAccount[50],strUser_id[50];
if(!OpenFileForReadWrite())
return ;
try{
m_pConnection.CreateInstance(__uuidof(Connection));
m_pRecordset.CreateInstance(__uuidof(Recordset));
recordnum=m_pConnection->Open("DSN=stat","test","test",-1);
sprintf(putfilestr,"%20s %30s %40s %30s\n","用户编码","用户帐号","用户Email","用户办公电话");
fwrite(putfilestr,strlen(putfilestr),1,fpout);
while(!feof(fpin))
{
fscanf(fpin,"%s",account);
//sprintf(SqlStr,"select a.user_id,a.account, b.email,b.phone_office from userbasicinfo a,usercontactinfo b where a.account='%s' and b.user_id=a.user_id",account);
strcpy(SqlStr,"select * from region");
recordnum=m_pRecordset->Open(SqlStr,m_pConnection.GetInterfacePtr(),adOpenKeyset,adLockOptimistic,adCmdText);
//用 recordnum=m_pRecordset->Open(SqlStr,m_pConnection.GetInterfacePtr(),adOpenDynamic,adLockOptimistic,adCmdText);
// 也出错
recordnum=m_pRecordset->adoEOF;
//执行到此出错，为何。跳到catch(...)
if(!m_pRecordset->adoEOF)
{
TheUser_id=m_pRecordset->GetCollect("user_id");

TheAccount=m_pRecordset->GetCollect("account");
TheEmail=m_pRecordset->GetCollect("email");
ThePhone_office=m_pRecordset->GetCollect("phone_office");
sprintf(putfilestr,"%20s %30s %40s %30s\n",TheUser_id.bstrVal,TheAccount.bstrVal,TheEmail.bstrVal,ThePhone_office.bstrVal);
fwrite(putfilestr,strlen(putfilestr),1,fpout);
}//end if
m_pRecordset->Close();
}//end while
}//end try
catch(_com_error *e)
{

//CString Error = e->ErrorMessage();
//char Error[500];
strcpy(Error , (char*)e->Description());
AfxMessageBox(e->ErrorMessage());
}
catch(_com_error e)
{

//CString Error = e->ErrorMessage();
strcpy(Error , (char*)e.Description());
//AfxMessageBox(e->ErrorMessage());
AfxMessageBox(Error);
}
catch(...)
{
AfxMessageBox("ado 出错");
}

m_pRecordset->Close();;
m_pConnection->Close();
m_pConnection->Release();
CloseAllFile();
}
// 执行到recordnum=m_pRecordset->adoEOF; 出错 为何
// 请那位大侠指点

[xwchena]

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