MDAC 2.5 SDK - ADO
Bof, EOF, And Bookmark Properties Example (VC )
The first function in this example uses the BOF and EOF properties to display a message if a user tries to move past the first or last record of a Recordset. It uses the Bookmark property to let the user flag a record in a Recordset and return to IT LATER.
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#import "c: / program files / compon files / system / ado / msado15.dll" /
NO_NAMESPACE RENAME ("EOF", "endoffile")
#include
#include
#include
#include "bofbeofbookmark.h"
// Function Declarations
Inline void testhr (hResult x) {if failed (x) _com_issue_error (x);
Void Bofx (Void);
Void Bookmarkx (Void);
Void PrintProvideRrror (_ConnectionPtr PConnection);
Void PrintComerror (_COM_ERROR & E);
///
///
// bofx function ////
///
///
void main ()
{
IF (Failed (:: Coinitialize (null)))
Return;
Bofx ();
// clear the screen for the next dispial
SYSTEM ("CLS");
Bookmarkx ();
Printf ("Press Any Key To Continue ...");
Getch ();
:: Couninitialize ();
}
///
///
// bofx function ////
///
///
Void Bofx (Void)
{
// define ado object Pointers.
// Initialize Pointers on Define.
// Thase Are In The AdoDB :: Namespace
_RecordSetPtr Rstpublishers = null; // define Other Variables
HRESULT HR = S_OK;
Iadorecordbinding * picrs = null; // interface Pointer Declared.
CPBLISHERS PUBLS;
BSTR_T STRCNN ("provider = SQLOLEDB; DATA SOURCE = SRV;"
"InTIAL CATALOG = PUBS; User ID = SA; Password =;");
_BSTR_T STRMESSAGE;
_variant_t varbookmark;
INT INTCOMMAND = 0;
_VARIANT_T TEMPPUBLISHER;
Try
{
// Open RecordSet with data from Publishers Table.
TESTHR (Rstpublishers.createInstance));
Rstpublishers-> cursortype = adopenStatic;
// Use client cursor to enable AbsolutePosition Property.
Rstpublishers-> CursorLocation = aduseclient;
Rstpublishers-> Open ("SELECT PUB_ID, PUB_NAME FROM PUBLISHERS"
"Order by Pub_Name", Strcnn, AdopenStatic,
Adlockbatchoptimistic, adcmdtext);
// Open an iporecordbinding interface Pointer
// Which Will BE Used for Binding Recordset to a class
TESTHR (Rstpublishers-> QueryInterface
__UUIDOF (Iadorecordbinding), (LPVOID *) & PICRS)))));
// bind the recordset to a c class here
TESTHR (Picrs-> Bindtorecordset);
Rstpublishers-> MoveFirst ();
While (True) // Continuous Loop.
{
// Display Information About The Current Record? // DISPLAY INFORMATION
// and get User INPUT
Printf ("Publisher:% S / N Record% D OF% D / N / N",
PUBLS.LP_PUBNAMESTATUS == ADFLDOK?
PUBLS.M_SZP_PUBNAME: "
Rstpublishers-> AbsolutePosition,
Rstpublishers-> RecordCount);
Printf ("Enter Command: / N");
Printf ("[1 - next / 2 - previous // n");
Printf ("3 - Set Bookmark / 4 - Go to Bookmark // N");
Printf ("5 - quit] / n");
Scanf ("% D", & intcommand;
IF (IntCommand <1) || (intcommand> 4)))
Break; // out of range entry exits program loop.
Switch (int Commommand)
{
//Move forward or backward, trapping for bof or eof
Case 1:
RSTPUBLISHERS-> MOVENEXT ();
IF (Rstpublishers-> endoffile)
{
Printf ("/ NCANNOT MOVE PAST The Last Record."
"TRY AGAIN ... / N");
Rstpublishers-> movelast ();
}
Break;
Case 2:
Rstpublishers-> movPrevious ();
IF (Rstpublishers-> BOF)
{
Printf ("/ NCANNOT MOVE BEFORE THE FIRST RECORD."
"TRY AGAIN ... / N");
Rstpublishers-> MoveFirst ();
}
Break;
// Store The Bookmark of The Current Record.
Case 3:
Varbookmark = RSTPUBLISHERS-> BOOKMARK;
// go to the record indeicated by the
// stored bookmark
Break;
Case 4:
// Check for WHETHER BOOKMARK SET for A Record
IF (varbookmark.vt == vt_empty)
Printf ("NO Bookmark Set! / N");
Else
Rstpublishers-> Bookmark = varbookmark;
Break;
DEFAULT:
Break;
}
}
// Clean Up Objects Before Exit.
Rstpublishers-> close ();
// Release The Iadorecordset Interface Here
IF (PICRS)
Picrs-> Release ();
}
Catch (_COM_ERROR & E)
{
Printf ("Error In Bofx ... / N");
// Notify the user of errors if any.
_VARIANT_T VTCONNECT = RSTPUBLISHERS-> getActiveConnection ();
// getActiveConnection Returns Connect Stringiffiffiffiffiff IF Connection
// is Not Open, Else Returns Connection Object.
Switch (vtconnect.vt)
{
Case VT_BSTR:
Printf ("Error: / N");
Printf ("CODE =% 08LX / N", E.Error ());
Printf ("Message =% S / N", E.ERRORMESSAGE ());
Printf ("Source =% S / N", (LPCSTR) E.Source ());
Printf ("Description =% S / N", (LPCSTR) E.DESCRIPTION ());
Break; Case vt_dispatch:
PRINTPROVIDERROR (VTCONNECT);
Break;
DEFAULT:
Printf ("ERRORS OCCURED.");
Break;
}
Printf ("Press Any Key To Continue ...");
Getch ();
}
}
///
///
// Bookmarkx Function //
///
///
Void Bookmarkx (Void)
{
// define ado object Pointers.
// Initialize Pointers on Define.
// There Are IN The AdoDB :: Namespace.
_RecordSetPtr Rstauthors = NULL;
// define other variables
Iadorecordbinding * picrs = null; // interface Pointer Declared.
Cauthors Authrs;
HRESULT HR = S_OK;
_BSTR_T STRCNN ("provider = SQLOLEDB; DATA SOURCE = SRV;"
"InTIAL CATALOG = PUBS; User ID = SA; Password =;");
_variant_t vbookmark;
// Variable Declaration for Safe Arrays.
SafeArray far * PSA;
// define array / variant variant.
Vbookmark.vt = vt_Array | vt_variant;
SafeArraybound Rgsabound [1];
Rgsabound [0] .llbound = 0;
Rgsabound [0] .CELEMENTS = 11;
Long ii = 0;
Try
{
RSTAUTHORS.CREATEINSTANCE (__ uuidof (recordset);
// set the cursor location
RSTAUTHORS-> CURSORLOCATION = ADUSECLIENT;
RSTAUTHORS-> PutactiveConnection ((_ variant_t) strcnn;
// Open Authors Table
Testhr (Rstauthors-> Open ("Select * from authors", strcnn,
AdoPenStatic, AdlockBatchOptimistic, AdcmdText);
// Open an iporecordbinding interface Pointer
// Which we'll Use for binding recordset to a class
Testhr (Rstauthors-> queryinterface (__ uuidof (iporecordbinding),
(Lpvoid *) & picrs)));
// bind the recordset to a c class here
TESTHR (Picrs-> BindtorecordSet);
Printf ("Number of Records Before Filtering:% D / N", RSTAUTHORS-> RecordCount);
// Create SafeArrays to Store Array of Variant
PSA = SafeArrayCreate (VT_VARIANT, 1, RGSABOUND);
// Store Bookmark of Every Other Record Into An Array.
While ((! Rstauthors-> Endoffile) && (ii <11))
{
SafearrayPutelement (PSA, & II, & RSTAUTHORS-> BOOKMARK);
// II = II 1;
II ;
RSTAUTHORS-> Move (2);
}
Vbookmark.parray = PSA;
// filter the record with the array of bookmarks.
RSTAUTHORS-> PUT_FILTER (Vbookmark);
Printf ("Number of Records After Filtering:% D / N",
RSTAUTHORS-> RecordCount);
RSTAUTHORS-> MOVEFIRST ();
While (! RSTAUTHORS-> endoffile)
{
Printf ("% D% S / N", Rstauthors-> AbsolutePosition,
Authrs.lau_lnamestatus == Adfldok?
Authrs.m_szau_lname: "
RSTAUTHORS-> MOVENEXT ();
}
// Release the adorecordset interface.
IF (PICRS)
Picrs-> Release ();
// Clean Up Objects Before Exit.
RSTAUTHORS-> Close ();
}
Catch (_COM_ERROR & E)
{
// Notify the user of errors if any.
_VARIANT_T VTCONNECT = RSTAUTHORS-> getActiveConnection ();
// getActiveConnection Returns Connect Stringiffiffiffiffiff IF Connection
// is Not Open, Else Returns Connection Object.
Switch (vtconnect.vt)
{
Case VT_BSTR:
Printf ("Error: / N");
Printf ("CODE =% 08LX / N", E.Error ());
Printf ("Message =% S / N", E.ERRORMESSAGE ());
Printf ("Source =% S / N", (LPCSTR) E.Source ());
Printf ("Description =% S / N", (LPCSTR) E.DESCRIPTION ());
Break;
Case vt_dispatch:
PRINTPROVIDERROR (VTCONNECT);
Break;
DEFAULT:
Printf ("ERRORS OCCURED.");
Break;
}
}
}
///
// ///printprovidererror function ////
///
///
Void PrintProvideRRROR (_ConnectionPtr PConnection)
{
// Print Provider Errors from Connection Object.
// Perr is a record object in the connection's error.
Errorptr Perr = NULL;
Long ncount = 0;
LONG i = 0;
IF ((PConnection-> Errors-> count)> 0)
{
Ncount = pConnection-> Errors-> count;
// Collection Ranges from 0 to ncount -1.
For (i = 0; i { Perr = pConnection-> Errors-> GetItem (i); Printf ("Error Number:% X / T% S / N", Perr-> Number, (Lpcstr) Perr-> description); } } } BofeofBookmark.h: #include "icrsint.h" // this class extracts only pubid, lastname and hire_date Class Cpublishers: Public Cadorecordbinding { Begin_ado_binding (cpublishers) // column title is the 2nd field in the recordset ADO_VARIABLE_LENGTH_ENTRY2 (1, Advarchar, M_SZP_PUBID, SizeOf (M_SZP_PUBID), LP_PUBIDSTATUS, FALSE // column type is the 3rd field in the recordset ADO_VARIABLE_LENGTH_ENTRY2 (2, Advarchar, M_SZP_Pubname, SizeOf (M_SZP_Pubname), LP_Pubnamestatus, TRUE END_ADO_BINDING () PUBLIC: CHAR M_SZP_PUBID; Ulong LP_PBIDSTATUS; CHAR M_SZP_PUBNAME [40]; Ulong lp_pubnamestatus; } // this class extracts only authorlastname Class Cauthors: Public Cadorecordbinding { Begin_ado_binding (Cauthors) // column authorlname is the 2nd field in the recordset ADO_VARIABLE_LENGTH_ENTRY2 (2, Advarchar, M_Szau_lname, SizeOf (m_szau_lname), Lau_lnamestatus, False END_ADO_BINDING () PUBLIC: Char m_szau_lname [40]; Ulong lau_lnamestatus;};
