String^ constring=L"datasource=localhost;port=3306;username=root;password=Bbaco2013";


				 MySqlCommand^ cmdDataBase=gcnew MySqlCommand("select * from biblioteca.login WHERE = usuario=@usuario AND contraseña=@contraseña;",conDataBase);

					cmdDataBase->Parameters->AddWithValue("@Raul", username_txt->Text);
					cmdDataBase->Parameters->AddWithValue("@root", password_txt->Text);