问从XE6 asp.net调用dll

EN

function GeraChave(Action : PAnsiChar; StrCrip : PAnsiChar; Cnpj : PAnsiChar; idPC: PAnsiChar): PAnsiChar; stdcall;
var
 KeyLen : Integer;
 KeyPos : Integer;
 OffSet : Integer;
 Dest, Key : String;
 SrcPos : Integer;
 SrcAsc : Integer;
 TmpSrcAsc : Integer;
 Range, I : Integer;
 matKey : Array[0..7] of String;
begin
  if (StrCrip = '') Then
  begin
    Result:= '';
    Exit;
  end;

  for I := 0 to 8 do
    matKey[I] := Copy(idPC, I, 1);

  Key := 'A#%tgNh*'+ matKey[0] +'UJklo'+ matKey[1] + 'O' + cnpj + 'O' +
         '798DS'+ matKey[2] +'Cea'+ matKey[3] +'SEc%7*I'+ matKey[4] +'u@Ed#'+
         matKey[5] +'f$f'+ matKey[6] +'%g&j-9'+ matKey[7] +'sc';

  Dest := '';
  KeyLen := Length(Key);
  KeyPos := 0;
  SrcPos := 0;
  SrcAsc := 0;
  Range := 256;

  if (Action = UpperCase('C')) then
  begin
    Randomize;
    OffSet := Random(Range);
    Dest := Format('%1.2x',[OffSet]);
    for SrcPos := 1 to Length(StrCrip) do
    begin
      SrcAsc := (Ord(StrCrip[SrcPos]) + OffSet) Mod 255;
      if KeyPos < KeyLen then KeyPos := KeyPos + 1 else KeyPos := 1;

      SrcAsc := SrcAsc Xor Ord(Key[KeyPos]);
      Dest := Dest + Format('%1.2x',[SrcAsc]);
      OffSet := SrcAsc;
    end;
  end
  Else if (Action = UpperCase('D')) then
  begin
    OffSet := StrToInt('$' + copy(StrCrip,1,2));
    SrcPos := 3;
    repeat
      SrcAsc := StrToInt('$' + copy(StrCrip,SrcPos,2));
      if (KeyPos < KeyLen) Then KeyPos := KeyPos + 1 else KeyPos := 1;
      TmpSrcAsc := SrcAsc Xor Ord(Key[KeyPos]);
      if TmpSrcAsc <= OffSet then TmpSrcAsc := 255 + TmpSrcAsc - OffSet
      else TmpSrcAsc := TmpSrcAsc - OffSet;
      Dest := Dest + Chr(TmpSrcAsc);
      OffSet := SrcAsc;
      SrcPos := SrcPos + 2;
    until (SrcPos >= Length(StrCrip));
  end;

 Result := PAnsiChar(Dest);
end;

 Exports
 GeraChave;

 begin
end.

public partial class _Default : System.Web.UI.Page
{

    [DllImport(@"H:\FTP\HOME\Web\testes\dllDelphi\Bin\DllChave.dll", 
               CallingConvention = CallingConvention.StdCall,
               CharSet = CharSet.Ansi)]

    public static extern string GeraChave(string xAction, string StrCrip, string Cnpj, string idPC);

    protected void Page_Load(object sender, EventArgs e)
    {
        string str = "A75BD3FD" + "|15/12/2016|" + "04564521020004";
        string xTp = "C";
        string Cnpj = "04564521020004";
        string IDPC = "A75BD3FD";
        string xRes = "";

        xRes = GeraChave(xTp, str, Cnpj, IDPC);

    }
}