老是抛出connection没被初始化，怎么破

Question

private void FrmSysLogin_Load(object sender, EventArgs e)
{
conStr = @"Data Source=2011-20131004OT;Initial Catalog=Bank;Integrated Security=true";

    }
    private void btnLogin_Click(object sender, EventArgs e)
    {
        SqlConnection connection = new SqlConnection(conStr);
        SqlCommand cmd = new SqlCommand();
        connection .Open ( );
        cmd .CommandText = " SELECT*FROM Bank WHERE cardID@='6301'&&<='6310' AND pwd=='888888'";
        SqlParameter paraID = new SqlParameter();
        paraID.ParameterName = "cardID";
        paraID.DbType = System.Data.DbType.String;
        paraID.SqlDbType = System.Data.SqlDbType.Char;
        paraID.Direction = System.Data.ParameterDirection.InputOutput;
        paraID.IsNullable = true;
        paraID.Value = "10000";
        cmd.Parameters.Add(paraID);
        SqlParameter paraPWD = new SqlParameter();
        paraPWD.ParameterName = "pwd";
        paraPWD.DbType = System.Data.DbType.String;
        paraPWD.SqlDbType = System.Data.SqlDbType.Char;
        paraPWD.Direction = System.Data.ParameterDirection.InputOutput;
        paraPWD.IsNullable = true;
        paraPWD.Value = "888888";
        cmd.Parameters.Add(paraPWD);
        SqlDataReader reader = cmd.ExecuteReader();
        if (reader.HasRows)
        {
            ;
            MessageBox.Show("登录成功！");
        }
        else
        {
            MessageBox.Show("登录失败！");
        }
        connection.Close();

Answer 1

SqlDataReader reader = cmd.ExecuteReader();
就是上面这条语句老是说CONNECTION没有被初始化。。。。怎么办

快来人哇~~~~求打救