2010发邮件附件收到乱码。

String filename = L"E:\\附件\\2.txt";   //需要添加的附件文件
IdMessage1-> MessageParts-> Add();

new TIdAttachmentFile(IdMessage1-> MessageParts,filename);

IdMessage1->MessageParts->Items[0]->FileName = L"=?gbk?B?" +  ExtractFileName( filename) + L"?=";

发送可以，但接收的时候显示的不是附件，而是乱码。下面是邮件内容：
This is a multi-part message in MIME format --EpftIiTK2Nd9EQBt3=_VB0idgG2t5eaJAL Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Memo1 --EpftIiTK2Nd9EQBt3=_VB0idgG2t5eaJAL Content-Type: application/octet-stream; name="=?GB2312?B?PT9nYms/Qj8yLnR4dD89?=" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="=?GB2312?B?PT9nYms/Qj8yLnR4dD89?=" 1eLA78rHuL28/qOhDQoxMjM0NTY3ODkxMjM0NTY3ODkNCnRlc3QgYXR0YWNoDQqy4srUuL28/sTc srvE3MrVtb2how== --EpftIiTK2Nd9EQBt3=_VB0idgG2t5eaJAL--
要怎么样才能发送附件呢？
[解决办法]
刚试了试,不用设置ba64;关键是你的IdMessage1的设置.我测试的例子

 IdSMTP1->Username ="zzbinfo";
  IdSMTP1->Password ="2629339zzb";
  IdSMTP1->Host ="smtp.163.com";
  IdSMTP1->Port =25;

  IdMessage1->Body->Clear();
 IdMessage1->Encoding = meMIME;
  IdMessage1->ContentType = "multipart/alternative";//"text/html";
   IdMessage1->ContentTransferEncoding="base64";
   IdMessage1->CharSet="utf-8";

  IdMessage1->Subject="测试";
  IdMessage1->Body->Text ="This is a text！！！";
  IdMessage1->From->Text="zzbinfo@163.com";
  IdMessage1->Recipients->EMailAddresses="6171153@qq.com";
String filename = L"c:\\test.txt";   //需要添加的附件文件
IdMessage1-> MessageParts-> Add();

  TIdAttachmentFile  *AttachEmail  = new TIdAttachmentFile(IdMessage1-> MessageParts,filename);
  AttachEmail->ContentType="application/octet-stream";
  AttachEmail->ContentDisposition="attachment";
  AttachEmail->ContentTransfer="base64";
  AttachEmail->FileName=ExtractFileName(filename);




  try{
  IdSMTP1->Connect();
  IdSMTP1->Authenticate();
  IdSMTP1->Send(IdMessage1);
  }

  catch(...)
  {
  ShowMessage("发送失败!");
  return;
  }
 ShowMessage("发送成功\!");
}