100分!!!!!!!!谁给我答案!!!!!!!!!!!!!
我要做一个操作数据库的DLL,DLL库中有一个函数:
extern "C" __declspec(dllexport) VARIANT getRow(){
::CoInitialize(NULL);
HRESULT hr;
_ConnectionPtr pConn;
pConn.CreateInstance(__uuidof(Connection));
hr=pConn->Open("DSN=zktest","","",0);
_RecordsetPtr pRs;
pRs.CreateInstance(__uuidof(Recordset));
hr=pRs->Open("warehouse",pConn.GetInterfacePtr(),adOpenDynamic,adLockOptimistic,adCmdTable);
_variant_t vRowsFetched=pRs->GetRows(adGetRowsRest);
hr=pRs->Close();
hr=pConn->Close();
::CoUninitialize();
return vRowsFetched;
}
主程序中这样调用:
void CTestPuiCtlDlg::OnDisplay()
{
MessageBox("aaa");
_variant_t data=pui_select_group();//这里出现0x*******不能访问***的错误
MessageBox("ccc");
LONG rows;
LONG cols;
SafeArrayGetUBound(data.parray,2,&rows);
SafeArrayGetUBound(data.parray,1,&cols);
m_data.SetRows(rows+1);
m_data.SetCols(cols+1);
_variant_t vVal;
_variant_t vShow;
CString str;
for(LONG i=0;i<=rows;i++){
for(LONG j=0;j<=cols;j++){
SafeArrayGetElement(data.parray,&j,&vVal);
VariantChangeType(&vShow,&vVal,0,VT_BSTR);
str=(char*)_bstr_t(vShow);
m_data.SetTextMatrix(i+1,j+1,str);
}
}
}
这是为什么?我在getRow()中加过一些AfxMessageBox(),一直到这个函数运行完也没出现这个错误,所以,我怀疑可能是参数返回时出的问题。
后来我又把程序改成:
extern "C" __declspec(dllexport) IDispatch* pui_select_group(){
::CoInitialize(NULL);
HRESULT hr;
_ConnectionPtr pConn;
pConn.CreateInstance(__uuidof(Connection));
hr=pConn->Open("DSN=zktest","","",0);
_RecordsetPtr pRs;
pRs.CreateInstance(__uuidof(Recordset));
hr=pRs->Open("warehouse",pConn.GetInterfacePtr(),adOpenDynamic,adLockOptimistic,adCmdTable);
_variant_t vRowsFetched=pRs->GetRows(adGetRowsRest);
hr=pRs->Close();
hr=pConn->Close();
::CoUninitialize();
return (IDispatch*)vRowsFetched;
}
和
void CTestPuiCtlDlg::OnDisplay()
{
MessageBox("aaa");
IDispatch* id=pui_select_group();//还是这,这次出现Runtime error.
MessageBox("bbb");
_variant_t data=new _variant_t(id);
MessageBox("ccc");
LONG rows;
LONG cols;
SafeArrayGetUBound(data.parray,2,&rows);
SafeArrayGetUBound(data.parray,1,&cols);
m_data.SetRows(rows+1);
m_data.SetCols(cols+1);
_variant_t vVal;
_variant_t vShow;
CString str;
for(LONG i=0;i<=rows;i++){
for(LONG j=0;j<=cols;j++){
SafeArrayGetElement(data.parray,&j,&vVal);
VariantChangeType(&vShow,&vVal,0,VT_BSTR);
str=(char*)_bstr_t(vShow);
m_data.SetTextMatrix(i+1,j+1,str);
}
}
}
我被这个问题搞了一天了,快疯了,我家帮帮我吧,分不够可以加。