PublishSubscribeSession.BeginSubscribe Method
Begins an asynchronous operation to subscribe to the presence session.
Namespace: Microsoft.Rtc.Collaboration.Presence
Assembly: Microsoft.Rtc.Collaboration (in Microsoft.Rtc.Collaboration.dll)
Syntax
'Declaration
Public Overridable Function BeginSubscribe ( _
userCallback As AsyncCallback, _
state As Object _
) As IAsyncResult
'Usage
Dim instance As PublishSubscribeSession
Dim userCallback As AsyncCallback
Dim state As Object
Dim returnValue As IAsyncResult
returnValue = instance.BeginSubscribe(userCallback, _
state)
public virtual IAsyncResult BeginSubscribe(
AsyncCallback userCallback,
Object state
)
Parameters
- userCallback
Type: System.AsyncCallback
The method to be called when the asynchronous operation is completed.
- state
Type: System.Object
A user-provided object that distinguishes this particular asynchronous operation from other asynchronous operations.
Return Value
Type: System.IAsyncResult
An IAsyncResult that references the asynchronous operation.
Exceptions
| Exception | Condition |
|---|---|
| InvalidOperationException | Thrown when the subscription is not in a valid state. |
Remarks
UCMA allows subscription to be reused. Hence, the application can re-subscribe to the same subscription after it has been unsubscribed.