BeginOpen Method (AsyncCallback, Object)

CommunicationObject.BeginOpen Method (AsyncCallback, Object)


Begins an asynchronous operation to open a communication object.

Namespace:   System.ServiceModel.Channels
Assembly:  System.ServiceModel (in System.ServiceModel.dll)

Public Function BeginOpen (
	callback As AsyncCallback,
	state As Object
) As IAsyncResult


Type: System.AsyncCallback

The AsyncCallback delegate that receives notification of the completion of the asynchronous open operation.

Type: System.Object

An object, specified by the application, that contains state information associated with the asynchronous open operation.

Return Value

Type: System.IAsyncResult

The IAsyncResult that references the asynchronous open operation.

Exception Condition

The communication object is not in a Opened or Opening state and cannot be modified.


The communication object is in a Closing or Closed state and cannot be modified.


The communication object is in a Faulted state and cannot be modified.


The default interval of time that was allotted for the operation was exceeded before the operation was completed.

The OnBeginOpen(TimeSpan, AsyncCallback, Object) method calls OnOpening and OnBeginOpen(TimeSpan, AsyncCallback, Object) if the communication object is initially in the Created state.

To insert processing after a communication object transitions to a closing state due to the invocation of a synchronous Open operation, use the Open method.

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 3.0
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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