title: C# Winforms Npgsql 3.0.5 "An operation already in progress" error when trying to run multiple commands inside same connection
body: <p>I'm trying to run the following snippet in C# Winforms. This piece of code is working well with pgsql 2.2.6 adapter. What correction can be made in order to work fine with pgsql3.0.5 adapter? Thanks.</p>
  
  <pre><code>NpgsqlConnection conn = new NpgsqlConnection(MainForm2.MyConString);
          {
              conn.Open();
              using (NpgsqlCommand cmd = new NpgsqlCommand("SELECT rfid,name,sc_id from passenger ORDER by name", conn))
              {
                  NpgsqlDataReader dr = cmd.ExecuteReader();
                  while (dr.Read())
                  {
                      var obj = new PassengerClass
                      {
                          RFID = dr.GetString(0),
                          Name = dr.GetString(1),
                          sc_id = dr.GetInt32(2)
                      };
                      s = dr.GetString(0);
                      try { ret.Add(s, obj); }
                      catch (Exception ex) { SM.Debug("Fail to add RFID Name in hash RFID:" + s + ex.ToString()); }
                  }
              }
              MainForm2.PassHash = ret;
              try
              {
                  using (NpgsqlCommand cmd = new NpgsqlCommand(string.Format("UPDATE place set useridx ={0} where useridx=0", MainForm2.userIDX), conn))
                      cmd.ExecuteNonQuery();
  
                  using (NpgsqlCommand cmd = new NpgsqlCommand(string.Format("UPDATE zonename set useridx ={0} where useridx=0", MainForm2.userIDX), conn))
                      cmd.ExecuteNonQuery();
              }
              catch (Exception ex)
              {
                  SM.Debug("Error on update users IDX for place and zone with value 0 :" + ex.ToString());
              }
  </code></pre>
  
  <p>So, at the second command statement it gives me the following error: </p>
  
  <blockquote>
    <p>A first chance exception of type 'System.InvalidOperationException'
    occurred in Npgsql.dll</p>
    
    <p>Additional information: An operation is already in progress.</p>
  </blockquote>
  
  <p><a href="https://i.stack.imgur.com/jbaDI.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/jbaDI.jpg" alt="enter image description here"></a></p>
  
  <p><strong>EDIT</strong> Additional info:
  <a href="https://i.stack.imgur.com/wG2Mo.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/wG2Mo.jpg" alt="enter image description here"></a></p>