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This article mainly shows you "how to achieve WCF callback", the content is easy to understand, clear, hope to help you solve your doubts, let the editor lead you to study and learn "how to achieve WCF callback" this article.

Because the WCF callback method does not run in the main thread, if the WCF callback method needs to update the interface related to the result of the asynchronous call, such as the lbMessage control in this example, you need to Marshal the callback call to the synchronization context of the current main program interface. We can marshal the call using SynchronizationContext and its SendOrPostCallback delegate:

Public ExplorerClientForm () {InitializeComponent (); m_synchronizationContext = SynchronizationContext.Current;} private SynchronizationContext m_synchronizationContext

Then the WCF callback method is modified to:

/ / callback method void OnTransferCompleted (IAsyncResult result) {Stream stream = m_service.EndTransferDocument (result); result.AsyncWaitHandle.Close (); SendOrPostCallback callback = delegate {lbMessage.Text = string.Format ("The file {0} had been transfered sucessfully.", m_doc.FileName);}; m_synchronizationContext.Send (callback,null);}

When calling an asynchronous method, I define the service proxy object as a private field because the calls to the BeginTransferDocument () and EndTransferDocument () methods may be in different method bodies. If you want to define the service object as a local variable, you can pass the proxy object to the method's asyncState parameter when you call the BeginTransferDocument () method, and then get the exact service proxy object through IAsyncResult before calling the EndTransferDocument () method:

M_service.BeginTransferDocument (masked doc.OnTransferCompletedOnTransferComplete masking service)

After you pass in m_service as an asyncState object, you can get the service proxy object based on it before calling the EndTransferDocument () method:

IDocumentsExplorerService m_service = result.AsyncState as IDocumentsExplorerService; Stream stream = m_service.EndTransferDocument (result); / / the above is all the content of the article "how to implement WCF callback". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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