AudioVideoFlow.BeginRetrieve Method (AsyncCallback, Object)
Begins to retrieve the AudioVideoFlow.
Namespace: Microsoft.Rtc.Collaboration.AudioVideo
Assembly: Microsoft.Rtc.Collaboration (in Microsoft.Rtc.Collaboration.dll)
Syntax
'Declaration
Public Function BeginRetrieve ( _
userCallback As AsyncCallback, _
state As Object _
) As IAsyncResult
'Usage
Dim instance As AudioVideoFlow
Dim userCallback As AsyncCallback
Dim state As Object
Dim returnValue As IAsyncResult
returnValue = instance.BeginRetrieve(userCallback, _
state)
public IAsyncResult BeginRetrieve(
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 AudioVideoFlow is not in the Active state or when there is already an asynchronous operation in progress. |
Examples
The following example retrieves an AudioVideoFlow from a hold state.
C# Retrieving a call.
if (audioVideoFlow.HoldStatus != HoldType.None)
{
audioVideoFlow.BeginRetrieve(
new AsyncCallback(delegate(IAsyncResult result)
{
try
{
audioVideoFlow.EndRetrieve(result);
}
catch (RealTimeException e)
{
// handle exception
throw e;
}
// audioVideoFlow is now retrieved.
}),
this);
}