(转)TComboBox patch for Delphi 7

unit D7ComboBoxStringsGetPatch;
 
// The patch fixes TCustomComboBoxStrings.Get method for empty string item in Delphi .
 
interface
 
{$IF RTLVersion <> 15.0}
 
'This patch is intended for Delphi 7 only';
 
{$IFEND}
 
implementation
 
uses
 
  Windows, SysUtils, StdCtrls;
 
resourcestring
 
  RsPatchingFailed = 'TCustomComboBoxStrings.Get patching failed.';
 
type
 
  TPatchResult = (prNotNeeded, prOk, prError);
 
function PatchCode(RoutineStartAddr: Pointer; PatchOffset: Cardinal; OriginalCode: Pointer;
 
  OriginalCodeLen: Cardinal; PatchedCode: Pointer; PatchedCodeLen: Cardinal): TPatchResult;
 
const
 
  JmpOpCode = $25FF;
 
type
 
  PPackageThunk = ^TPackageThunk;
 
  TPackageThunk = packed record
 
    JmpInstruction: Word;
 
    JmpAddress: PPointer;
 
  end;
 
var
 
  CodeStart: Pointer;
 
  BytesWritten: DWORD;
 
begin
 
  if FindClassHInstance(System.TObject) <> HInstance then
 
    with PPackageThunk(RoutineStartAddr)^ do
 
      if JmpInstruction = JmpOpCode then
 
        RoutineStartAddr := JmpAddress^
 
      else
 
      begin
 
        Result := prError;
 
        Exit;
 
      end;
 
  CodeStart := Pointer(LongWord(RoutineStartAddr) + PatchOffset);
 
  if CompareMem(CodeStart, OriginalCode, OriginalCodeLen) then
 
  begin
 
    if WriteProcessMemory(GetCurrentProcess, CodeStart, PatchedCode, PatchedCodeLen, BytesWritten) and
 
      (BytesWritten = PatchedCodeLen) then
 
    begin
 
      FlushInstructionCache(GetCurrentProcess, CodeStart, PatchedCodeLen);
 
      Result := prOk;
 
    end
 
    else
 
      Result := prError;
 
  end
 
  else
 
    Result := prNotNeeded;
 
end;
 
type
 
  TCustomComboBoxStringsHack = class(TCustomComboBoxStrings);
 
function AddrOfTCustomComboBoxStringsGet: Pointer;
 
begin
 
  Result := @TCustomComboBoxStringsHack.Get;
 
end;
 
procedure PatchTCustomComboBoxStringsGet;
 
const
 
  OriginalCode: Cardinal  = $74FFF883; // CMP EAX, - | JZ  +$
 
  PatchedCode: Cardinal   = $7E00F883; // CMP EAX,   | JLE +$
 
  PatchOffset             = $1F;
 
  // for DEBUG DCU by Pavel Rogulin
 
  OriginalCodeD: Cardinal = $FFF07D83;
 
  PatchedCodeD: Cardinal  = $00F07D83;
 
  PatchOffsetD            = $2E;
 
var
 
  PatchResult: TPatchResult;
 
begin
 
  PatchResult := PatchCode(AddrOfTCustomComboBoxStringsGet, PatchOffset, @OriginalCode, SizeOf(OriginalCode),
 
    @PatchedCode, SizeOf(PatchedCode));
 
  if PatchResult = prNotNeeded then
 
    PatchResult := PatchCode(AddrOfTCustomComboBoxStringsGet, PatchOffsetD, @OriginalCodeD, SizeOf(OriginalCodeD),
 
      @PatchedCodeD, SizeOf(PatchedCodeD));
 
  case PatchResult of
 
    prError:
 
      begin
 
        if IsConsole then
 
          WriteLn(ErrOutput, RsPatchingFailed)
 
        else
 
          MessageBox(, PChar(RsPatchingFailed), nil, MB_OK or MB_ICONSTOP or MB_TASKMODAL);
 
        RunError();
 
      end;
 
  end;
 
end;
 
initialization
 
  PatchTCustomComboBoxStringsGet;
 
end.

官方BUG解决地址:

http://cc.embarcadero.com/item/18872