| 发表于：2007-08-16 10:55:5115楼 得分:0 |
msdn的示例代码如下，我原来用的是int，其他的都和示例基本一样，可就是不成，最后发现是类型不同，呵呵，人家用的是short，俺用的是int或者long，哈哈
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=myserver; "
"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, " ", " ", adconnectunspecified);
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);
}
}
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