在Delphi 7中，我正在开发一个实现对象的库，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。
我用于此次通话的代码如下：
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()，则会返回错误87，“参数不正确。”
这没有多大意义，因为如果我只是将InformationLevel从BatterySerialNumber更改为BatteryUniqueID，代码就可以正常运行。另外，我在hbat之前的代码中的其他调用中使用了电池的句柄（GetSerialNumber）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，所以这是不是问题。
有什么想法吗？我真的很茫然。
答案 0 :(得分：12)
它似乎与作为@dwOut传递的dwOut变量相关的问题，此变量表示DeviceIoControl的var lpBytesReturned参数，该参数定义为
function DeviceIoControl(hDevice: THandle; dwIoControlCode: DWORD; lpInBuffer: Pointer;
nInBufferSize: DWORD; lpOutBuffer: Pointer; nOutBufferSize: DWORD;
var lpBytesReturned: DWORD; lpOverlapped: POverlapped): BOOL; stdcall;
所以用
替换你的代码 Result := DeviceIoControl(hbat, IOCTL_BATTERY_QUERY_INFORMATION, @bqi,
SizeOf(bqi), Serial, SerialSize, dwOut, nil);
必须解决问题。
另请查看此msdn条目Enumerating Battery Devices中翻译为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, 0x00, 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, 0, 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, nil, GUID_DEVCLASS_BATTERY, idev, did)) then
begin
try
cbRequired := 0;
SetupDiGetDeviceInterfaceDetail(hdev, @did, nil, 0, cbRequired, nil);
if (ERROR_INSUFFICIENT_BUFFER= GetLastError()) then
begin
pdidd:=AllocMem(cbRequired);
try
pdidd.cbSize := SizeOf(TSPDeviceInterfaceDetailData);
if (SetupDiGetDeviceInterfaceDetail(hdev, @did, pdidd, cbRequired, cbRequired, nil)) then
begin
hBattery :=CreateFile(pdidd.DevicePath, GENERIC_READ OR GENERIC_WRITE, FILE_SHARE_READ OR FILE_SHARE_WRITE, nil, 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), dwOut, nil)) then
begin
lpOutBuffer:=AllocMem(MAX_PATH);
try
ZeroMemory(lpOutBuffer,MAX_PATH);
bqi.InformationLevel:=InformationLevel;
if DeviceIoControl(hBattery, IOCTL_BATTERY_QUERY_INFORMATION, @bqi, SizeOf(BATTERY_QUERY_INFORMATION), lpOutBuffer, 255, dwOut,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.
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.
答案 1 :(得分：0)
总之，代码@RRUZ和我在Windows 7以及其他第三方应用程序中发布的工作正常。它们不适用于在Windows XP下检索序列号。我也在WinXP和7下测试了在完全相同的硬件上安装了操作系统，结果相同（在Windows 7下成功，而不是在Windows XP下）。
在WinXP下，BatterySerialNumber的{{1}}成员的值IOCTL_BATTERY_QUERY_INFORMATION似乎不受支持，但Windows SDK文档中没有直接记录。据记录，无效条目应返回InformationLevel的错误1（ERROR_INVALID_FUNCTION），但在这种情况下返回87（对于无效参数）。我认为这是因为枚举中的值无效，所以它使参数无效，但我不完全确定。
感谢所有人的帮助，尤其是@RRUZ超越自我！
（另外，似乎可以从电池的唯一ID中提取序列号（使用GetLastError()作为BatteryUniqueID成员）并从唯一ID中删除制造商名称和设备名称这是一个可怕的黑客，但它是Windows XP的半可行解决方案。）