AudioVideoCall.BeginTransfer Method (Call, CallTransferOptions, AsyncCallback, Object)
Initiates a transfer request to the remote participant.
Namespace: Microsoft.Rtc.Collaboration.AudioVideo
Assembly: Microsoft.Rtc.Collaboration (in Microsoft.Rtc.Collaboration.dll)
Syntax
'Declaration
Public Function BeginTransfer ( _
callToReplace As Call, _
callTransferOptions As CallTransferOptions, _
userCallback As AsyncCallback, _
state As Object _
) As IAsyncResult
'Usage
Dim instance As AudioVideoCall
Dim callToReplace As Call
Dim callTransferOptions As CallTransferOptions
Dim userCallback As AsyncCallback
Dim state As Object
Dim returnValue As IAsyncResult
returnValue = instance.BeginTransfer(callToReplace, _
callTransferOptions, userCallback, _
state)
public IAsyncResult BeginTransfer(
Call callToReplace,
CallTransferOptions callTransferOptions,
AsyncCallback userCallback,
Object state
)
Parameters
- callToReplace
Type: Microsoft.Rtc.Collaboration.Call
The call to be replaced.
- callTransferOptions
Type: Microsoft.Rtc.Collaboration.CallTransferOptions
Call transfer options. This parameter can be null.
- 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 |
|---|---|
| ArgumentNullException | Thrown when the callToReplace value is null. |
| ArgumentException | Thrown when the callTransferOptions parameter is specified with unsupported headers, or is used to override transferor value by any endpoint other than an ApplicationEndpoint or is of type Unattended. |
| InvalidOperationException | Thrown when the callToReplace is not in the Established or the current call is not in a valid state to initiate a transfer operation. |
Remarks
Initiates a transfer request to the remote participant, of the current call to replace another existing call in Attended mode.
This is a Supervised transfer since the operation involves another call and it waits for success/failure notifications from the remote participant regarding how the transfer is being carried out at the remote side. When the transfer is successfully completed by the existing remote participant, the current call is terminated. If it fails, the call is not affected.
If callToReplace is passed as the instance of the call initiating the transfer, then this would be considered as the self-transfer.