type
  TCommandType = (ctEmptyCommand, ctAdd, ctModify);

  TCommandTypeConvert = class
  public
    class function CommandToString(ACommand: TCommandType): string;
    class function StringToCommand(const AStrCommand: string): TCommandType;
  end;

implementation

class function TCommandTypeConvert.CommandToString
  (ACommand: TCommandType): string;
begin
  Result := GetEnumName(TypeInfo(TCommandType), Ord(ACommand));
end;

class function TCommandTypeConvert.StringToCommand(const AStrCommand: string)
  : TCommandType;
begin
  Result := TCommandType(GetEnumValue(TypeInfo(TCommandType), AStrCommand));
end;