udpserver,udpclient 用delphi7 7封装在dll 里，出现的问题

Question

udpserver,udpclient 用delphi7 7封装在dll 里，udpserver 接受一个设备的udp数据，udpclient 发送数据到设备，
用xe 调用dll 接收数据正常，发送数据报av 00409D85 的内存错误，用delphi 7 调用这个dll 收发数据都正常，这是怎么回事，希望高手能解答下！

Answer 1

library ZHPRReadCard;uses
  SysUtils,
  IdBaseComponent,
  IdComponent,
  IdUDPBase,
  IdUDPServer,
  IdUDPClient,
  System,
  IdSocketHandle,
  Dialogs,
  Windows,
  Messages,
  Classes;  type
  TClientClass = class  public
     IDUDPS: TIdUDPServer;
     sIDUDPS: TIdUDPClient;
    procedure IDUDPRead(Sender: TObject; AData: TStream; ABinding: TIdSocketHandle);
    procedure openudp;
    procedure  closeudp;
    procedure StartReadCard;
    procedure Openontjdq;
    constructor Create;
    destructor Destroy; override;  end;
var
 fhand:hwnd;
 fipaddress:string;
 fport:Integer;
 FClient:TClientClass;
// myudp:TIdUDPServer;
 const   WM_YOURMSG=WM_USER+200;
{$R *.res}
function StrToHex(AStr: String):String;
var
  i: Integer;
begin
  result := '';
  for i := 1 to Length(AStr) do
    result := result + IntToHex(ord(AStr[i]), 2);
end;function readinit(hand:hwnd;ipaddress:string;port:Integer):Boolean;stdcall;
begin
  fhand:=hand;
  fipaddress:=ipaddress;
  fport:=port;
   if FClient = nil then
  begin
    FClient := TClientClass.Create;
    Result := True;
  end
  else
  begin
    Result := False;
  end;end;function OpenRead:Boolean;stdcall;
begin
   if FClient<>nil then
   begin
    FClient.openudp;
    Result:=True;
   end
   else Result:=False;
end;function CloseRead:Boolean;stdcall;
begin
   if FClient<>nil then
   begin
    FClient.closeudp;
    Result:=True;
   end
   else Result:=False;
end;function StareReadcard:Boolean;stdcall;
begin
  if FClient<>nil then
  begin
    FClient.StartReadCard;
    Result:=True;
  end
  else Result:=False;
end;function Openontjdq:Boolean;stdcall;
begin
   if FClient<>nil then
  begin
    FClient.Openontjdq;
    Result:=True;
  end
  else Result:=False;
end;
exports
 OpenRead,
 closeread,
 StareReadcard,
 Openontjdq,
 readinit;
{ TClientClass }constructor TClientClass.Create;
begin
   inherited;
  IdUDPS := TIdUDPServer.Create(nil);
  sIdUDPS := TIdUDPClient.Create(nil);
  IDUDPS.DefaultPort:=fport;
  IDUDPS.ThreadedEvent:=True;
  IDUDPS.BufferSize:=8192;
  IdUDPS.OnUDPRead := IDUDPRead;  
  //IdUDPS.Active := True;
end;destructor TClientClass.Destroy;
begin
  FClient.Free;
  inherited;
end;procedure TClientClass.Openontjdq;
var
  ssh:array[0..5] of Byte;
begin
  ssh[0]:=$05;
  ssh[1]:=$00;
  ssh[2]:=$3C;
  ssh[3]:=$01;
  ssh[4]:=$FD;
  ssh[5]:=$63;
  sIDUDPS.SendBuffer(fipaddress,fport,ssh,Length(ssh));
end;procedure TClientClass.StartReadCard;  // 开始读卡
var
  ssh:array[0..4] of Byte;begin
  ssh[0]:=$04;
  ssh[1]:=$00;
  ssh[2]:=$01;
  ssh[3]:=$DB;
  ssh[4]:=$4B;  sIDUDPS.SendBuffer(fipaddress,fport,ssh,Length(ssh));end;procedure TClientClass.openudp;
begin
  IDUDPS.Active:=True;
end;procedure TClientClass.closeudp;
begin
  IDUDPS.Active:=False;
end;procedure TClientClass.IDUDPRead(Sender: TObject; AData: TStream;
  ABinding: TIdSocketHandle);
var
  fRecvUDPstring:string;
  DataStringStream:tstringstream;
  cDataParam: TCopyDataStruct;
  msg: AnsiString;
begin
     DataStringStream:=tstringstream.Create('');
 TRY
   DataStringStream.CopyFrom(adata,adata.Size);
   fRecvUDPstring:=DataStringStream.DataString;
  // RemostIP:= ABinding.PeerIP;
 finally
   DataStringStream.Free;
 end;
   msg:=StrToHex(fRecvUDPstring);
   if fhand<>0 then
   begin
     cDataParam.dwData := WM_YOURMSG;
     cDataParam.cbData := length(msg)* sizeof(char)+1;
     cDataParam.lpData := @msg[1];
     SendMessage(fhand, WM_COPYDATA,0, LPARAM(@cDataParam));
   end;
end;
beginend.
这是代码帮忙看看？谢谢

Answer 2

readinit里用到了string,
不知道你调用的程序是用什么写的,如果不是delphi估计就不要用string了
如果是delphi,那最好引用sharemm之类的东西,并用相同的delphi编译dll和exe吧或许是别的问题也不一定