连接ACCESS数据库是发生错误，请指教。

private void but_login_Click(object sender, EventArgs e)
  {
  string constring = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\Documents and Settings\\Administrator\\桌面\\xx.mdb;Persist Security Info=False ";
  OdbcCommand comm = new OdbcCommand();
  OdbcConnection conn = new OdbcConnection();
  conn.ConnectionString = constring;
  comm.Connection = conn;
  conn.Open();
  comm.CommandText = "select * from user where user_name="+teb_username.Text +"and user_password="+teb_password.Text;
  OdbcDataReader reader = new OdbcDataReader();
  reader = comm.ExecuteReader();
  if (reader.HasRows)
  {
  label1.Text = "yes";
  }
  else
  label1.Text = "no";
   
  }

代码如上，但是在OdbcDataReader reader = new OdbcDataReader();上出错，提示信息是：
system.data.odbc.odbcdatareader 未定义构造函数。

谢谢指教

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OdbcDataReader reader = new OdbcDataReader();
  reader = comm.ExecuteReader();

这两句话，改成:

OdbcDataReader reader = comm.ExecuteReader();

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comm.ExecuteReader()的返回就是一个rea