| INT EnableEvents( |
| |
HWND hEventWnd, |
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| |
UINT uEventMsg |
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| ); |
The EnableEvents method enables event notifications
using Windows messages.
This method has been deprecated and may be unavailable in future
releases. It was designed for use in legacy single-threaded applications
and requires the application to have a message pump to process event
messages. It should not be used with applications which are designed
to execute as a service or those which do not have a graphical user
interface.
Applications should use the RegisterEvent
method to register an event handler which is invoked when an event
occurs.
Parameters
- hEventWnd
- Handle to the window which will receive the client notification
messages. This parameter must specify a valid window handle. If a
NULL handle is specified, event notification will be disabled.
- uEventMsg
- The message that is received when a client event occurs. This
value must be greater than 1024.
Return Value
If the method succeeds, the return value is zero. If the method
fails, the return value is WHOIS_ERROR. To get extended error
information, call GetLastError.
Remarks
The EnableEvents method is used to request that
notification messages be posted to the specified window whenever a
client event occurs. This allows an application to monitor the status
of different client operations, such as a file transfer.
The wParam argument will contain the client handle, the low
word of the lParam argument will contain the event ID, and the
high word will contain any error code. If no error has occurred, the
high word will always have a value of zero. The following events may
be generated:
| Value |
Description |
| WHOIS_EVENT_CONNECT |
The connection to the server has completed. The high
word of the lParam parameter should be checked, since this
notification message will be posted if an error has
occurred. |
| WHOIS_EVENT_DISCONNECT |
The server has closed the connection to the client. The
client should read any remaining data and disconnect. |
| WHOIS_EVENT_READ |
Data is available to read by the calling process. No
additional messages will be posted until the client has read at
least some of the data. This event is only generated if the
client is in asynchronous mode. |
| WHOIS_EVENT_WRITE |
The client can now write data. This notification is sent
after a connection has been established, or after a previous
attempt to write data has failed because it would result in a
blocking operation. This event is only generated if the client is
in asynchronous mode. |
| WHOIS_EVENT_TIMEOUT |
The network operation has exceeded the specified timeout
period. The client application may attempt to retry the
operation, or may disconnect from the server and report an error
to the user. |
| WHOIS_EVENT_CANCEL |
The current operation has been canceled. Under most
circumstances the client should disconnect from the server and
re-connect if needed. After an operation has been canceled, the
server may abort the connection or refuse to accept further
commands from the client. |
To disable event notification, call the DisableEvents
method.
Requirements
Minimum Desktop Platform: Windows 7 Service Pack 1
Minimum Server Platform: Windows Server 2008 R2 Service Pack 1
Header File: cstools11.h
Import Library: cswhov11.lib
See Also
DisableEvents,
RegisterEvent
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