MDAC 2.5 SDK - ADO

CursorType, LockType, and EditMode Properties Example (VC++)

See Also

This example demonstrates setting the CursorType and LockType properties before opening a Recordset. It also shows the value of the EditMode property under various conditions. The EditModeOutput function is required for this procedure to run.

#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 declaration
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);};
void EditModeX(void);
void EditModeOutput(char *, int);
void PrintProviderError(_ConnectionPtr pConnection);
void PrintComError(_com_error &e);

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

     EditModeX();

    ::CoUninitialize();
}

///////////////////////////////////////////////////////////
//                                                       //
//      EditModeX Function                               //
//                                                       //
///////////////////////////////////////////////////////////
void EditModeX(void)
{
    // Define ADO object pointers.
    // Initialize pointers on define.
    // These are in the ADODB::  namespace.
    _RecordsetPtr     pRstEmployees = NULL;
    _ConnectionPtr    pConnection  = NULL;

    HRESULT hr = S_OK;

    _bstr_t strCnn("Provider=sqloledb;Data Source=srv;"
        "Initial Catalog=Pubs;User Id=sa;Password=;");

    try
    {
        // Open a connection
        TESTHR(pConnection.CreateInstance(__uuidof(Connection)));
        hr = pConnection->Open(strCnn,"","",NULL);

        // Open recordset with data from Employee table 
        TESTHR(pRstEmployees.CreateInstance(__uuidof(Recordset)));

        pRstEmployees->CursorLocation = adUseClient;
        pRstEmployees->CursorType = adOpenStatic;
        pRstEmployees->LockType  = adLockBatchOptimistic;

        pRstEmployees->Open("Employee",
             _variant_t((IDispatch *) pConnection,true),
            adOpenStatic,adLockBatchOptimistic,adCmdTable);

        // Show the EditMode property under different editing states.
        pRstEmployees->AddNew ();
        pRstEmployees->Fields->Item["emp_id"]->Value = 
            (_bstr_t)("T-T55555M");
        pRstEmployees->Fields->Item["fname"]->Value = 
            (_bstr_t)("temp_fname");
        pRstEmployees->Fields->Item["lname"]->Value = 
            (_bstr_t)("temp_lname");
        EditModeOutput("After AddNew: ", pRstEmployees->EditMode);

        pRstEmployees->UpdateBatch(adAffectCurrent);
        EditModeOutput("After Update: ", pRstEmployees->EditMode);
        
        pRstEmployees->Fields->Item["fname"]->Value = (_bstr_t)("test");
        EditModeOutput("After Edit: ", pRstEmployees->EditMode);

        // Delete new record because this is a demonstration.
        pConnection->Execute("DELETE FROM Employee WHERE emp_id = "
            "'T-T55555M'", NULL, adCmdText);

        // Clean up objects before exit.
        pRstEmployees->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);
    }
}

///////////////////////////////////////////////////////////
//                                                       //
//      EditModeOutput() Function                        //
//                                                       //
///////////////////////////////////////////////////////////
void EditModeOutput(char *strTemp, int intEditMode)
{
    // Print report based on the value of the EditMode property.
    printf("\n%s", strTemp);
    printf("\n  EditMode = ");

    switch (intEditMode)
    {
        case adEditNone :
            printf("adEditNone");
            break;
        case adEditInProgress :
            printf("adEditInProgress");
            break;
        case adEditAdd :
            printf("adEditAdd");
            break;
    }
}

///////////////////////////////////////////////////////////
//                                                       //
//      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("\n\t Error number: %x\t%s", pErr->Number,
                (LPCSTR)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);
}