itemx.cpp

来自「visual c++ 很全的ado的sample」· C++ 代码 · 共 266 行

#import "C:\Program Files\Common Files\System\ADO\msado15.dll" \
    no_namespace rename("EOF", "EndOfFile")

#include <ole2.h>
#include <stdio.h>
#include <conio.h>

// Function declarations
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);};
void ItemX(void);
void PrintProviderError(_ConnectionPtr pConnection);
void PrintComError(_com_error &e);

//////////////////////////////////////////////////////////
//                                                      //
//       Main Function                                  //
//                                                      //
//////////////////////////////////////////////////////////

void main()
{
    if(FAILED(::CoInitialize(NULL)))
        return;

        ItemX();

     //Wait here for the user to see the output
     printf("Press any key to continue...");
     getch();
    ::CoUninitialize();
}

//////////////////////////////////////////////////////////
//                                                      //
//       ItemX Function                                 //
//                                                      //
//////////////////////////////////////////////////////////

void ItemX(void) 
{
    HRESULT  hr = S_OK;

    // Define ADO object pointers.
    // Initialize pointers on define.
    // These are in the ADODB::  namespace.
   _ConnectionPtr  pConnection  = NULL;
   _RecordsetPtr   pRst     = NULL;
   _CommandPtr     pCmd     = NULL;
   _ParameterPtr   pPrm     = NULL;
    FieldPtr       pFld     = NULL;

    // Other Variables.
    _bstr_t strCnn("Provider=sqloledb;Data Source=srv;"
            "Initial Catalog=pubs;User Id=sa;Password=;");
    _variant_t    Column[9];
    _variant_t    vIndex;

   try
    {
       // Open connection.
        TESTHR(pConnection.CreateInstance(__uuidof(Connection)));

        TESTHR(pRst.CreateInstance(__uuidof(Recordset)));

        TESTHR(pCmd.CreateInstance(__uuidof(Command)));

        //Set the array with the authors table field (column) names
        Column[0] = "au_id";
        Column[1] = "au_lname";
        Column[2] = "au_fname";
        Column[3] = "phone";
        Column[4] = "address";
        Column[5] = "city";
        Column[6] = "state";
        Column[7] = "zip";
        Column[8] = "contract";

        _bstr_t strText("SELECT * FROM authors WHERE state = ?");
        pCmd->CommandText = strText;

        pPrm = pCmd->CreateParameter("ItemXparm", adChar, adParamInput,
            2, "CA");
        pCmd->Parameters->Append(pPrm);

        pConnection->Open(strCnn, "", "", NULL);
        pCmd->ActiveConnection = pConnection;

        // Connection and CommandType are omitted because 
        // a Command object is provided.
        _variant_t Conn;
        Conn.vt = VT_ERROR;
        Conn.scode = DISP_E_PARAMNOTFOUND;

        pRst->Open((_variant_t((IDispatch *) pCmd)),Conn,adOpenStatic,
            adLockReadOnly, -1);

        printf("The Parameters collection accessed by index...\n");

        vIndex = (short) 0;
        pPrm = pCmd->Parameters->GetItem(&vIndex);
        printf("Parameter name = '%s', value = '%s'\n",
            (LPCSTR)pPrm->Name, (LPSTR)(_bstr_t)pPrm->Value);

        printf("\nThe Parameters collection accessed by name...\n");
        pPrm = pCmd->Parameters->Item["ItemXparm"];
        printf("Parameter name = '%s', value = '%s'\n",
            (LPCSTR)pPrm->Name, (LPSTR)(_bstr_t)pPrm->Value);

        printf("\nThe Fields collection accessed by index...\n");
        pRst->MoveFirst();
        long limit = 0;
        limit = ((pRst->Fields->Count) - 1);
        int intLineCnt = 8; 
        for (short iIndex = 0; iIndex <= limit; iIndex++)
        {
            vIndex = iIndex;
            intLineCnt++;
            if (intLineCnt%15 == 0)
            {
                printf("\nPress any key to continue...\n");
                getch();
            }
            pFld = pRst->Fields->GetItem(&vIndex);
            printf("Field %d : Name =  '%s', ", iIndex,
                (LPCSTR)pFld->GetName());
            _variant_t FldVal = pFld->GetValue();  

            // Because Value is the default property of a
            // Property object,the use of the actual keyword
            // here is optional.
            switch(FldVal.vt)
            {
                case (VT_BOOL):
                    if(FldVal.boolVal)
                    {
                        printf("Value = 'True'");
                    }
                    else
                    {
                        printf("Value = 'False'");
                    }
                    printf("\n");
                    break;
                case (VT_BSTR):
                    printf("Value = '%s'",
                        (LPCSTR)(_bstr_t)FldVal.bstrVal);
                    printf("\n");
                    break;
                case (VT_I4):
                    printf("Value = '%s'",(LPCSTR)FldVal.iVal);
                    printf("\n");
                    break;
                case (VT_EMPTY):
                    printf("Value = '%s'",(LPCSTR)FldVal.lVal);
                    printf("\n");
                    break;
                default:
                    break;
            }
        }

        printf("\nThe Fields collection accessed by name...\n");
        pRst->MoveFirst();
        for (iIndex = 0; iIndex <= 8; iIndex++)
        {
            intLineCnt++;
            if (intLineCnt%15 == 0)
            {
                printf("\nPress any key to continue...\n");
                getch();
            }
            pFld = pRst->Fields->GetItem(Column[iIndex]);
            printf("Field name = '%s', ",(LPCSTR)pFld->GetName());
            _variant_t FldVal = pFld->GetValue();

            // Because Value is the default property of a
            // Property object,the use of the actual keyword
            // here is optional.
            switch(FldVal.vt)
            {
                case (VT_BOOL):
                    if(FldVal.boolVal)
                    {
                        printf("Value = 'True'");
                    }
                    else
                    {
                        printf("Value = 'False'");
                    }
                    printf("\n");
                    break;
                case (VT_BSTR):
                    printf("Value = '%s'",
                        (LPCSTR)(_bstr_t)FldVal.bstrVal);
                    printf("\n");
                    break;
                case (VT_I4):
                    printf("Value = '%s'",(LPCSTR)FldVal.iVal);
                    printf("\n");
                    break;
                case (VT_EMPTY):
                    printf("Value = '%s'",(LPCSTR)FldVal.lVal);
                    printf("\n");
                    break;
                default:
                    break;
            }
        }
        // Clean up objects before exit.
        pRst->Close();
        pConnection->Close();
   }

   catch(_com_error &e)
   {
       // Notify the user of errors if any.
       // Pass a connection pointer accessed from the Recordset.
       PrintProviderError(pConnection);
       PrintComError(e);
   }
}

//////////////////////////////////////////////////////////
//                                                      //
//      PrintProviderError Function                     //
//                                                      //
//////////////////////////////////////////////////////////

void PrintProviderError(_ConnectionPtr pConnection)
{
    // Print Provider Errors from Connection object.
    // pErr is a record object in the Connection's Error collection.
    ErrorPtr    pErr  = NULL;

    if( (pConnection->Errors->Count) > 0)
    {
        long nCount = pConnection->Errors->Count;
        // Collection ranges from 0 to nCount -1.
        for(long i = 0; i < nCount; i++)
        {
            pErr = pConnection->Errors->GetItem(i);
            printf("\t Error number: %x\t%s", pErr->Number, 
                pErr->Description);
        }
    }
}

//////////////////////////////////////////////////////////
//                                                      //
//       PrintComError Function                         //
//                                                      //
//////////////////////////////////////////////////////////

void PrintComError(_com_error &e)
{
   _bstr_t bstrSource(e.Source());
   _bstr_t bstrDescription(e.Description());

    // Print Com errors.
   printf("Error\n");
   printf("\tCode = %08lx\n", e.Error());
   printf("\tCode meaning = %s\n", e.ErrorMessage());
   printf("\tSource = %s\n", (LPCSTR) bstrSource);
   printf("\tDescription = %s\n", (LPCSTR) bstrDescription);
}