BeginTransfer Method (Call, CallTransferOptions, AsyncCallback, Object)
Intiates a transfer request to the remote participant of the current call to replace another existing call in Attended type.
Namespace: Microsoft.Rtc.Collaboration
Assembly: Microsoft.Rtc.Collaboration (in Microsoft.Rtc.Collaboration.dll)
Syntax
'Declaration
Protected Function BeginTransfer ( _
callToReplace As Call, _
options As CallTransferOptions, _
userCallback As AsyncCallback, _
state As Object _
) As IAsyncResult
'Usage
Dim callToReplace As Call
Dim options As CallTransferOptions
Dim userCallback As AsyncCallback
Dim state As Object
Dim returnValue As IAsyncResult
returnValue = Me.BeginTransfer(callToReplace, _
options, userCallback, state)
protected IAsyncResult BeginTransfer(
Call callToReplace,
CallTransferOptions options,
AsyncCallback userCallback,
Object state
)
Parameters
- callToReplace
Type: Microsoft.Rtc.Collaboration..::..Call
The call to be replaced.
- options
Type: Microsoft.Rtc.Collaboration..::..CallTransferOptions
- userCallback
Type: System..::..AsyncCallback
The callback to be invoked when the operation is done.
- state
Type: System..::..Object
The state to be passed back to the callback.
Return Value
Type: System..::..IAsyncResult
An IAsyncResult that references this operation.
Exceptions
| Exception | Condition |
|---|---|
| ArgumentNullException | Thrown if the value is null. |
| ArgumentException | Thrown if the contains null or unsupported headers, contains null or unsupported MIME part headers, is used to override transferor value by any endpoint other than an Application. Endpoint is of type Unattended transfer. |
| InvalidOperationException | Thrown if the call is not in Established state. Current call is not in a valid state to initiate a transfer operation. |
Remarks
This is Supervised transfer since the operation involves another call and it waits for success/failure notifications from the remote regarding how the transfer is being carried out at the remote side. When the transfers is successfully by the existing remote participant, the current call is terminated. If it fails, the current 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.