Data Sharing
Overview
The io.Connect Channels are enabled by default when registering a VBA window as an io.Connect Window. You have to provide handler implementations for the Channel related events that will be raised due to interaction with the io.Connect Window instance - changing Channels and handling Channel data updates. When the io.Connect Channels are enabled, a Channel Selector box is available in the window title bar.
To check whether the Channel Selector is visible, use the GetChannelSupport
method of a GlueWindow
instance. To hide or show the Channel Selector, use the SetChannelSupport
method.
⚠️ Note that currently the
SetChannelSupport
method only hides or shows the Channel Selector, but doesn't enable or disable the Channel support. This can be done only during window registration.
' Hiding the Channel selector.
GlueWin.SetChannelSupport False
Handling Channel Change
The HandleChannelChanged
event is raised when the user changes the Channel using the Channel selection box in the window title bar. Use its handler to enable your app to react to Channel changes:
Private Sub GlueWin_HandleChannelChanged(ByVal GlueWindow As IGlueWindow, ByVal ChannelContext As IGlueContext, ByVal PrevChannelName As String)
On Error GoTo HandleErrors
Dim ChannelDataDynValue
Dim NewData
Dim NewChannelName As String
If channel Is Nothing Then
' Do something when the user deselects a Channel.
...
Else
ChannelDataDynValue = ChannelContext.GetReflectData("")
NewChannelName = ChannelDataDynValue("name")
NewData = ChannelDataDynValue("data")
' Do something when the user selects a new Channel.
...
End If
Exit Sub
HandleErrors:
' Handle exceptions.
End Sub
Subscribing for Channel Updates
To subscribe for Channel data updates, use the HandleChannelData
event which is raised in two cases:
- when the data in the currently selected Channel is updated;
- after the
HandleChannelChanged
event, when the user switches to another Channel;
Private Sub GlueWin_HandleChannelData(ByVal GlueWindow As IGlueWindow, ByVal ChannelUpdate As IGlueContextUpdate)
On Error GoTo HandleErrors
Dim ChannelDataDynValue
Dim Data
Dim ChannelName As String
ChannelDataDynValue = ChannelUpdate.GetContext.GetReflectData("")
ChannelName = ChannelDataDynValue("name")
Data = ChannelDataDynValue("data")
' Do something with the new data.
...
Exit Sub
HandleErrors:
' Handle exceptions.
End Sub
Publishing Data
To publish data to a Channel, you must update the shared context object dedicated the respective Channel. For details on how to update a shared context object, see the Shared Contexts > Updating a Context
section.
⚠️ Note that you must only update the value of the
"data"
property of the context object. The"name"
and"meta"
properties must not be modified, because they are specifically set for each Channel.