在Delphi 7中,我正在开发一个实现一个对象的库,该对象封装了有关连接到系统的电池的信息.除了检索电池的序列号外,它运行良好.
function TBattery.GetSerialNumber(hbat: THandle): boolean;
var
bqi: TBatteryQueryInformation;
Serial: PWideChar;
SerialSize,dwOut: DWORD;
begin
Result := False;
if hbat <> INVALID_HANDLE_VALUE then
begin
ZeroMemory(@bqi,SizeOf(bqi));
dwOut := 0;
bqi.BatteryTag := FBatteryTag;
bqi.InformationLevel := BatterySerialNumber;
SerialSize := 2048;
GetMem(Serial,SerialSize);
try
ZeroMemory(Serial,SerialSize);
Result := DeviceIoControl(hbat,IOCTL_BATTERY_QUERY_INFORMATION,@bqi,SizeOf(bqi),Serial,SerialSize,@dwOut,nil);
if Result then
FSerialNumber := Serial;
finally
FreeMem(Serial,SerialSize);
end;
end;
end;
不幸的是,DeviceIoControl()总是返回False,如果我之后检查GetLastError(),那么它返回错误87,“参数不正确”.
这没有多大意义,因为如果我只是简单地将InformationLevel从BatterySerialNumber更改为BatteryUniqueID,那么代码的效果非常好.另外,我在GetSerialNumber之前的代码中的其他调用中使用了电池的句柄(hbat)并且它们都工作正常,并且在此之后我也可以调用其他调用,所以这不是问题.
有任何想法吗？我真的很茫然.
解决方法
这个问题似乎与dwOut变量有关,它以@dwOut的形式传递,这个变量代表
DeviceIoControl的var lpBytesReturned参数,定义为
function DeviceIoControl(hDevice: THandle; dwIoControlCode: DWORD; lpInBuffer: Pointer; nInBufferSize: DWORD; lpOutBuffer: Pointer; nOutBufferSize: DWORD; var lpBytesReturned: DWORD; lpOverlapped: POverlapped): BOOL; stdcall;
所以替换你的代码
Result := DeviceIoControl(hbat,dwOut,nil);
必须解决问题.
WinAPI的
另请查看此msdn条目Enumerating Battery Devices中转换为delphi的代码,它可以帮助您检测代码的任何其他问题.
uses
SetupApi,Windows,SysUtils;
type
BATTERY_QUERY_INFORMATION_LEVEL = (
BatteryInformation,BatteryGranularityInformation,BatteryTemperature,BatteryEstimatedTime,BatteryDeviceName,BatteryManufactureDate,BatteryManufactureName,BatteryUniqueID,BatterySerialNumber);
TBatteryQueryInformationLevel = BATTERY_QUERY_INFORMATION_LEVEL;
_BATTERY_QUERY_INFORMATION = record
BatteryTag: ULONG;
InformationLevel: BATTERY_QUERY_INFORMATION_LEVEL;
AtRate: Longint;
end;
BATTERY_QUERY_INFORMATION = _BATTERY_QUERY_INFORMATION;
PBATTERY_QUERY_INFORMATION = ^BATTERY_QUERY_INFORMATION;
TBatteryQueryInformation = BATTERY_QUERY_INFORMATION;
const
GUID_DEVCLASS_BATTERY:TGUID='{72631E54-78A4-11D0-BCF7-00AA00B7B32A}';
//DEFINE_GUID( GUID_DEVCLASS_BATTERY,0x72631E54,0x78A4,0x11D0,0xBC,0xF7,0x00,0xAA,0xB7,0xB3,0x2A );
METHOD_BUFFERED = 0;
FILE_DEVICE_BATTERY = $00000029;
FILE_READ_ACCESS = $0001; // for files and pipes
IOCTL_BATTERY_QUERY_TAG =
(FILE_DEVICE_BATTERY shl 16) or (FILE_READ_ACCESS shl 14) or ($10 shl 2) or (METHOD_BUFFERED);
IOCTL_BATTERY_QUERY_INFORMATION =
(FILE_DEVICE_BATTERY shl 16) or (FILE_READ_ACCESS shl 14) or ($11 shl 2) or (METHOD_BUFFERED);
function GetBatteryInfo(InformationLevel : BATTERY_QUERY_INFORMATION_LEVEL) : string;
var
cbrequired : DWORD;
hdev : HDEVINFO;
idev : Integer;
did : TSPDeviceInterfaceData;
pdidd : PSPDeviceInterfaceDetailData;
hBattery : THandle;
bqi : TBatteryQueryInformation;
dwWait,dwOut : DWORD;
lpOutBuffer: PWideChar;
begin
// enumerate the batteries
hdev := SetupDiGetClassDevs(@GUID_DEVCLASS_BATTERY,nil,DIGCF_PRESENT OR DIGCF_DEVICEINTERFACE);
if ( INVALID_HANDLE_VALUE <> THandle(hdev) ) then
begin
idev:=0;//first battery
ZeroMemory(@did,SizeOf(did));
did.cbSize := SizeOf(did);
if (SetupDiEnumDeviceInterfaces(hdev,GUID_DEVCLASS_BATTERY,idev,did)) then
begin
try
cbrequired := 0;
SetupDiGetDeviceInterfaceDetail(hdev,@did,cbrequired,nil);
if (ERROR_INSUFFICIENT_BUFFER= GetLastError()) then
begin
pdidd:=AllocMem(cbrequired);
try
pdidd.cbSize := SizeOf(TSPDeviceInterfaceDetailData);
if (SetupDiGetDeviceInterfaceDetail(hdev,pdidd,nil)) then
begin
hBattery :=CreateFile(pdidd.DevicePath,GENERIC_READ OR GENERIC_WRITE,FILE_SHARE_READ OR FILE_SHARE_WRITE,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,0);
if (INVALID_HANDLE_VALUE <> hBattery) then
begin
try
ZeroMemory(@bqi,SizeOf(bqi));
// With the tag,you can query the battery info.
dwWait := 0;
if (DeviceIoControl(hBattery,IOCTL_BATTERY_QUERY_TAG,@dwWait,sizeof(dwWait),@bqi.BatteryTag,sizeof(bqi.BatteryTag),nil)) then
begin
lpOutBuffer:=AllocMem(MAX_PATH);
try
ZeroMemory(lpOutBuffer,MAX_PATH);
bqi.InformationLevel:=InformationLevel;
if DeviceIoControl(hBattery,SizeOf(BATTERY_QUERY_INFORMATION),lpOutBuffer,255,nil) then
Result:= WideCharToString(lpOutBuffer);
finally
FreeMem(lpOutBuffer);
end;
end;
finally
CloseHandle(hBattery)
end;
end;
end;
finally
FreeMem(pdidd);
end;
end;
finally
SetupDiDestroyDeviceInfoList(hdev);
end;
end;
end;
end;
begin
try
if not LoadsetupAPI then exit;
Writeln(GetBatteryInfo(BatterySerialNumber));
except
on E: Exception do
Writeln(E.ClassName,': ',E.Message);
end;
readln;
end.
WMI
最后请注意,您可以使用WMI检索相同的信息,在本例中使用BatteryStaticData WMI类
{$APPTYPE CONSOLE}
uses
SysUtils,ActiveX,ComObj,Variants;
// Battery Static Data
procedure GetBatteryStaticDataInfo;
const
WbemUser ='';
WbemPassword ='';
WbemComputer ='localhost';
wbemFlagForwardOnly = $00000020;
var
FSWbemLocator : OLEVariant;
FWMIService : OLEVariant;
FWbemObjectSet: OLEVariant;
FWbemObject : OLEVariant;
oEnum : IEnumvariant;
iValue : LongWord;
begin;
FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
FWMIService := FSWbemLocator.ConnectServer(WbemComputer,'root\WMI',WbemUser,WbemPassword);
FWbemObjectSet:= FWMIService.ExecQuery('SELECT SerialNumber FROM BatteryStaticData','WQL',wbemFlagForwardOnly);
oEnum := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
while oEnum.Next(1,FWbemObject,iValue) = 0 do
begin
Writeln(Format('SerialNumber %s',[String(FWbemObject.SerialNumber)]));// String
Writeln('');
FWbemObject:=Unassigned;
end;
end;
begin
try
CoInitialize(nil);
try
GetBatteryStaticDataInfo;
finally
CoUninitialize;
end;
except
on E:EOleException do
Writeln(Format('EOleException %s %x',[E.Message,E.ErrorCode]));
on E:Exception do
Writeln(E.Classname,':',E.Message);
end;
Writeln('Press Enter to exit');
Readln;
end.