Explain how to use the Begin and End methods on a Web Service to make an asynchronous method call.

Explain how to use the Begin and End methods on a Web Service to make an asynchronous method call.
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Every public Web method on a Web Service can be called either synchronously or asynchronously. To make an asynchronous call to a Web method, you call the method named Begin, where is the name of the method. This method requires a delegate to an appropriate callback method and returns a value of IAsyncResult. This value is returned as a parameter in the callback method. To retrieve the data returned by the Web method, call End, supplying a reference to the IAsyncResult returned by Begin. This will allow you to retrieve the actual data returned by the Web method.

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