为什么不运行查询：

Why not just run a query:

using (SqlConnection con = new SqlConnection(strConnect))
    {
    con.Open();
    using (SqlCommand com = new SqlCommand("SELECT COUNT(*) FROM players WHERE [name]=@AR1 AND lastname=@AR2 AND dob=@AR3", con))
        {
        com.Parameters.AddWithValue("@AR1", first);
        com.Parameters.AddWithValue("@AR2", second);
        com.Parameters.AddWithValue("@AR3", third);
        if( com.ExecuteScalar > 0)
            {
            // It exists already
            }
        }
    }