Problems with ECC Encrypt

[齐伟钢]

Dear,
        
I have got the key pair  using the following code(with Crypto++ 5.21).
But how can I use the key pair to encrypt a file or string?
        AutoSeededRandomPool rng;       
        DL_PrivateKey_EC<ECP> privkey;
        CryptoPP::DL_PublicKey_EC<CryptoPP::ECP> pubkey;
        privkey.Initialize(rng, ASN1::secp192r1());
        privkey.MakePublicKey(pubkey); 

Thanks!

your's sincerely

qiwg