DDClient DDE component interface details Properties, methods, events, types and constants

You can read the full details by downloading the control and reading the help file, from which the diagram is taken. The boxes are all hyperlinks in the help file. The diagram shows the main components of the control from a functional point of view. Use the object browser in the Visual Basic development environment for a syntactic view.

The control has a collection of conversations and a collection of channels (available services and topics) Each conversation has a collection of advise loops (hot links), a collection of request loops (warm links) and a collection of outstanding transactions The DDEData object allows the application to treat the data as a string or any binary format

Properties

FailedReturnString	User definable error return string
HandleEarlyAdvises	Enables the handling of data sent before an advise loop is fully established
idInst	The DDEML instance handle
Version	The DDClient version string

Methods

HandleEarlyAdvises	When true, data sent before an advise look is established is saved
Initialise	Initialises the DDEML library
Uninitialise	Unitialises the DDEML library
ReInitialise	Reinitialises the DDEML library
Connect	Creates a DDE conversation
Disconnect	Destroys a DDE conversation
Reconnect	Reconnects a conversation disconnected by the server
FindChannels	Finds service/topic pairs using DDE Wildconnect and adds them to the channels collection
ClearChannels	Removes channels found by FindChannels
Enumerate	Lists all the conversations, advise loops, request loops and channels
ProcessEarlyAdvises	Processes data sent early, before an advise loop is fully established
CreateConvContext	Creates a ConvContext object used in Connect
CreateQualityOfService	Create a Quality of Service object used in Connect
TransTypeName	Describes a transaction type
ConvKey	Converts a DDEML hConv to a key to the conversations collection
ItemKey	Converts a DDEML string handle to a key for an Advise Loop collection or a Request Loop collection
GetLastError	Returns the last DDEML error
QueryString	Returns the string for a DDEML string handle
TransKey	Converts DDEML transaction handle to a key to the transactions collection
ShowAboutBox	Shows the "About" dialog

Events

TransactionAdviseLoopStarted	An advise loop start has completed
DDEAdvise	Advise loop data arrival
TransactionAdviseLoopStopped	An advise loop has stopped
TransactionRequestLoopStarted	A request loop start has completed
DDENotify	Request loop notification
TransactionRequestLoopStopped	A request loop has stopped
TransactionPokeCompleted	A poke transaction has completed
TransactionRequestCompleted	A data request has completed
TransactionExecuteCompleted	An execute transaction has been acknowledged by the server
TransactionFailed	A transaction has failed
DDEDisconnect	The server has disconnected a conversation
DDERegister	A server has registered its service name. The service is added to the Channels collection
DDEUnregister	A server has unregistered its service name. The name is removed from the collection
LogFileError	An error has occurred in the log file

Collections

Conversations Collection	A Conversation Object collection. Each instance of the control has one of these collections
AdviseLoops Collection	An AdviseLoop Object collection, each conversation has one such collection
RequestLoops Collection	A RequestLoop Object collection, each conversation has one such collection
Transactions Collection	A Transaction Object collection, each conversation has one such collection
Channels Collection	A Channel Object collection

Objects

Conversation Object	Encapsulates a single DDE conversation
AdviseLoop Object	Encapsulates an advise loop
RequestLoop Object	Encapsulates a request loop
Transaction Object	An outstanding DDE transaction
Channel Object	A registered server recorded at a DDERegister event or channel found by the FindChannels method
DDEData Object	DDE data in string and binary format
LogFile Object	Handles logging output

Types, constants and enumerated values

ConvContext	An optional structure used in creating a conversation
QualityOfService	An optional structure used in creating a conversation
TransactionsEnum	The various transaction types
LogFileOptionsEnum	Logging output options
DMLEEREnum	DDEML error codes
Constants	Other enumerated values

Back to the RHA (Minisystems) Ltd home page
http://www.rhaminisys.com