Delphi -如何获得USB可移动硬盘驱动器和记忆棒列表？

Question

在我的应用程序(Delphi)中，我需要列出所有的USB存储设备。它们可以是闪存棒，也可以是外部存储驱动器。

有一个Jvcl组件JvDriveCombo，它具有DriveType属性--问题是如果我选择DriveType := Fixed，那么除了外部驱动器之外，它还列出内部驱动器(C:\、D:\等)。但是，我只想列出外部驱动器。

我相信有DeviceIoControl函数(我在MSDN上看到过)，但我不知道如何使用它。

我想知道是否有人能帮助我正确地列出USB存储设备的方式/代码？

谢谢。

编辑：

我刚刚找到了一些示例代码，并在这里发布：

uses .... jwawinbase, JwaWinIoctl;

procedure TForm1.Button1Click(Sender: TObject);
var
  DriveCmdStr: string;
  DriveHandle: THandle;
  ADriveLetter: string;
  hp: STORAGE_HOTPLUG_INFO;
  rlen: DWORD;
begin

  ADriveLetter := 'H';
  DriveCmdStr := Format('\\.\%s:', [ADriveLetter]);
  DriveHandle := CreateFile(PChar(DriveCmdStr), GENERIC_READ, FILE_SHARE_WRITE,
    nil, OPEN_EXISTING, 0, 0);

  if DriveHandle = INVALID_HANDLE_VALUE then
    Exit;

  DeviceIoControl(DriveHandle, IOCTL_STORAGE_GET_HOTPLUG_INFO, nil, 0, @hp,
    SizeOf(hp), @rlen, nil);

  CloseHandle(DriveHandle);

  if hp.MediaRemovable then
    showmessage('media removable');

end;

现在我只想知道如何枚举所有的驱动器字母。哪个是最有效的功能？

Answer 1

{$MINENUMSIZE 4}
const
  IOCTL_STORAGE_QUERY_PROPERTY =  $002D1400;

type
  STORAGE_QUERY_TYPE = (PropertyStandardQuery = 0, PropertyExistsQuery, PropertyMaskQuery, PropertyQueryMaxDefined);
  TStorageQueryType = STORAGE_QUERY_TYPE;

  STORAGE_PROPERTY_ID = (StorageDeviceProperty = 0, StorageAdapterProperty);
  TStoragePropertyID = STORAGE_PROPERTY_ID;

  STORAGE_PROPERTY_QUERY = packed record
    PropertyId: STORAGE_PROPERTY_ID;
    QueryType: STORAGE_QUERY_TYPE;
    AdditionalParameters: array [0..9] of AnsiChar;
  end;
  TStoragePropertyQuery = STORAGE_PROPERTY_QUERY;

  STORAGE_BUS_TYPE = (BusTypeUnknown = 0, BusTypeScsi, BusTypeAtapi, BusTypeAta, BusType1394, BusTypeSsa, BusTypeFibre,
    BusTypeUsb, BusTypeRAID, BusTypeiScsi, BusTypeSas, BusTypeSata, BusTypeMaxReserved = $7F);
  TStorageBusType = STORAGE_BUS_TYPE;

  STORAGE_DEVICE_DESCRIPTOR = packed record
    Version: DWORD;
    Size: DWORD;
    DeviceType: Byte;
    DeviceTypeModifier: Byte;
    RemovableMedia: Boolean;
    CommandQueueing: Boolean;
    VendorIdOffset: DWORD;
    ProductIdOffset: DWORD;
    ProductRevisionOffset: DWORD;
    SerialNumberOffset: DWORD;
    BusType: STORAGE_BUS_TYPE;
    RawPropertiesLength: DWORD;
    RawDeviceProperties: array [0..0] of AnsiChar;
  end;
  TStorageDeviceDescriptor = STORAGE_DEVICE_DESCRIPTOR;

function GetBusType(Drive: AnsiChar): TStorageBusType;
var
  H: THandle;
  Query: TStoragePropertyQuery;
  dwBytesReturned: DWORD;
  Buffer: array [0..1023] of Byte;
  sdd: TStorageDeviceDescriptor absolute Buffer;
  OldMode: UINT;
begin
  Result := BusTypeUnknown;

  OldMode := SetErrorMode(SEM_FAILCRITICALERRORS);
  try
    H := CreateFile(PChar(Format('\\.\%s:', [AnsiLowerCase(Drive)])), 0, FILE_SHARE_READ or FILE_SHARE_WRITE, nil,
      OPEN_EXISTING, 0, 0);
    if H <> INVALID_HANDLE_VALUE then
    begin
      try
        dwBytesReturned := 0;
        FillChar(Query, SizeOf(Query), 0);
        FillChar(Buffer, SizeOf(Buffer), 0);
        sdd.Size := SizeOf(Buffer);
        Query.PropertyId := StorageDeviceProperty;
        Query.QueryType := PropertyStandardQuery;
        if DeviceIoControl(H, IOCTL_STORAGE_QUERY_PROPERTY, @Query, SizeOf(Query), @Buffer, SizeOf(Buffer), dwBytesReturned, nil) then
          Result := sdd.BusType;
      finally
        CloseHandle(H);
      end;
    end;
  finally
    SetErrorMode(OldMode);
  end;
end;


procedure GetUsbDrives(List: TStrings);
var
  DriveBits: set of 0..25;
  I: Integer;
  Drive: AnsiChar;
begin
  List.BeginUpdate;
  try
    Cardinal(DriveBits) := GetLogicalDrives;

    for I := 0 to 25 do
      if I in DriveBits then
      begin
        Drive := Chr(Ord('a') + I);
        if GetBusType(Drive) = BusTypeUsb then
          List.Add(Drive);
      end;
  finally
    List.EndUpdate;
  end;
end;

Answer 2

您可以使用WMI访问此信息。如果使用此SQL，则可以访问有关已安装磁盘的信息。

select * from Win32_diskdrive where size<>NULL

此代码检索有关驱动器的信息。

procedure  TForm1.DoInventario(aWSQL:string; var mmResult:TMemo);
var
  Locator:ISWbemLocator;
  Services:ISWbemServices;
  SObject:ISWbemObject;
  ObjSet:ISWbemObjectSet;
  Enum:IEnumVariant;
  TempObj:OleVariant;
  Value:Cardinal;
  TS:TStrings;
begin

  try
    Locator := CoSWbemLocator.Create();
    // Conectar con el Servicio de WMI
    Services := Locator.ConnectServer(
        STR_LOCALHOST,        {ordenador local}
        STR_CIM2_ROOT,        {root}
        STR_EMPTY, STR_EMPTY, {usuario y password -en local no son necesarios-}
        STR_EMPTY,STR_EMPTY, 0, nil);
    // Acceder a los datos
    ObjSet := Services.ExecQuery(aWSQL, 'WQL',
                wbemFlagReturnImmediately and wbemFlagForwardOnly , nil);
    Enum :=  (ObjSet._NewEnum) as IEnumVariant;
    // Hemos encontrado algun objeto?
    while (Enum.Next(1, TempObj, Value) = S_OK) do begin
      SObject := IUnknown(TempObj) as ISWBemObject;
      // encontrado?
      if (SObject <> nil) then begin
        // Acceder a la propiedad
        SObject.Properties_;
        // Cargamos las propiedades
        TS := TStringList.Create();
        try
          TS.Add(SObject.GetObjectText_(0));
          // lo pasamos al memo
          mmResult.Lines.Text := mmResult.Lines.Text + TS.Text;
        finally
          FreeAndNil(TS);
        end;
      end;
    end;
  except
    // Recuperar excepciones
  end;

end;

您必须在您的使用中添加ActiveX和WbemScripting_TLB (必须导入)。这样，您就可以访问磁盘的所有信息。

要检索所有磁盘的字母，可以将对类Win32_LogicalDiskToPartition和Win32_DiskDrive.的访问组合起来(检索可以用相同的代码完成)

select * from Win32_LogicalDiskToPartition
select * from Win32_DiskDrive

如果您搜索WMI，您可以找到更多相关代码。

致以问候。

Answer 3

我不确定你是否只是想列举一下驱动器的字母？下面的for循环就是这样做的，它遍历所有的字母，不管是否有该字母的驱动器。

或者，如果您正在寻找一种不同的方法来寻找可移动驱动器，下面也有一个函数。(你的可能更好.)令人惊讶的是，在我的测试中，Windows.GetDriveType并不认为CD驱动器是可移动的。正如人们所预期的，USB驱动器被标记为可移动的。

  Function RemovableDrive(Drive: char): Boolean;
  begin
    Result := (Windows.GetDriveType(PChar(Drive + ':\')) = Windows.Drive_Removable);
  end;

  procedure TForm1.Button1Click(Sender: TObject);
  var
    Drive: Char;
  begin
    for Drive := 'A' to 'Z' do
      Memo1.Lines.Add('Drive: ' + Drive + ' is ' + BoolToStr(RemovableDrive(Drive), TRUE));
  end;