研究一下：
CheckForGracefulDisconnect
Checkfordisconnect
我原来直接DISCONNECT出错误，改为这样就没有问题了：
CheckForGracefulDisconnect(false);
if Connected then Disconnect;
------ If you receive an exception here, please read. ----------
If this is a SERVER
-------------------
The client has disconnected the socket normally and this exception is used to notify the
server handling code. This exception is normal and will only happen from within the IDE, not
while your program is running as an EXE. If you do not want to see this, add this exception
or EIdSilentException to the IDE options as exceptions not to break on.
From the IDE just hit F9 again and Indy will catch and handle the exception.
Please see the FAQ and help file for possible further information.
The FAQ is at http://www.nevrona.com/Indy/FAQ.html
If this is a CLIENT
-------------------
The server side of this connection has disconnected normaly but your client has attempted
to read or write to the connection. You should trap this error using a try..except.
Please see the help file for possible further information.
// ************************************************************* *)
raise EIdConnClosedGracefully.Create(RSConnectionClosedGracefully);
