Scroll Application Title on TaskBar with Delphi

procedure TForm1.Timer1timer(Sender: TObject);

begin

  Application.Title := Copy(Application.Title,

    2,Length(Application.Title)) + Application.Title[1];

  Application.Title := Application.Title[Length(Application.Title)] +

    Copy(Application.Title, 1,Length(Application.Title) - 1);

end;

Detect a keypress during a loop with Delphi

procedure TForm1.Button1Click(Sender: TObject);

var

  LoopAborted: Boolean;

  i: Integer;

begin

  LoopAborted := false;

  i := 0;

  repeat

    Caption := IntToStr(i);

    Application.ProcessMessages;

    if GetKeyState(VK_Escape) and 128 = 128 then

    begin

      LoopAborted :=

        true;

      Break;

    end;

    Inc(i);

  until i = 100000;

  if LoopAborted then

    ShowMessage('User has aborted the loop!');

end;

Example of controling the sound volume from Delphi

uses MMSystem;

type

  TVolumeRec = record

    case Integer of

      0: (LongVolume: Longint);

      1: (LeftVolume, RightVolume: Word);

  end;

const

  DeviceIndex = 5{0:Wave  1:MIDI  2:CDAudio  3:Line-In  4:Microphone  5:Master  6:PC-loudspeaker}

procedure SetVolume(aVolume: Byte);

var

  Vol: TVolumeRec;

begin

  Vol.LeftVolume := aVolume shl 8;

  Vol.RightVolume :=

  Vol.LeftVolume;

  auxSetVolume(UINT(DeviceIndex), Vol.LongVolume);

end;

function GetVolume: Cardinal;

var

  Vol: TVolumeRec;

begin

  AuxGetVolume(UINT(DeviceIndex), @Vol.LongVolume);

  Result := (Vol.LeftVolume + Vol.RightVolume) shr 9;

end;

Extract numbers from a string with Delphi

type

  TCharSet = set of Char;

function StripNonConforming(const S: string;

  const ValidChars: TCharSet): string;

var

  DestI: Integer;

  SourceI: Integer;

begin

  SetLength(Result, Length(S));

  DestI := 0;

  for SourceI := 1 to Length(S) do

    if S[SourceI] in

      ValidChars then

    begin

      Inc(DestI);

      Result[DestI] := S[SourceI]

    end;

  SetLength(Result,

    DestI)

end;

function StripNonNumeric(const S: string): string;

begin

  Result :=

    StripNonConforming(S, ['0'..'9'])

end;

Check if a disk is in the drive with Delphi

function DiskInDrive(Drive: Char): Boolean;

var

  ErrorMode: Word;

begin

  { make it upper case }

  if Drive in ['a'..'z'] then

    Dec(Drive, $20);

  { make sure it's a letter }

  if not (Drive in ['A'..'Z']) then

    raise EConvertError.Create('Not a valid drive ID');

  { turn off critical errors }

  ErrorMode := SetErrorMode(SEM_FAILCRITICALERRORS);

  try

    { drive 1 = a, 2 = b, 3 = c, etc. }

    if DiskSize(Ord(Drive) - $40) = -1 then

      Result := false

    else

      Result := true;

  finally

    { Restore old error mode }

    SetErrorMode(ErrorMode);

  end;

end;

A simple Delphi routine that gets the serial number of a disk

function FindVolumeSerial(const Drive: PChar): string;

var

  VolumeSerialNumber: DWORD;

  MaximumComponentLength: DWORD;

  FileSystemFlags: DWORD;

  SerialNumber: string;

begin

  Result := '';

  GetVolumeInformation(Drive, nil, 0, @

    VolumeSerialNumber, MaximumComponentLength, FileSystemFlags, nil, 0);

  SerialNumber :=

    IntToHex(HiWord(VolumeSerialNumber), 4) + ' - ' +

    IntToHex(LoWord(VolumeSerialNumber), 4);

  Result := SerialNumber;

end;