Asynchronous method call

What is asynchronous method call?
An asynchronous method call is a method used in .NET programming that returns to the caller immediately before processing is complete and without blocking the calling thread.

When an application calls an asynchronous method, it can run concurrently with the execution of the asynchronous method that is performing its task. An asynchronous method runs on a thread that is separate from the main application thread. The processing results are obtained by another call to another thread.

Asynchronous methods help optimize the execution of resources, resulting in a scalable application. These are used to perform time-consuming tasks such as opening large files, connecting to remote computers, querying a database, calling web services, and ASP.NET web forms.

The asynchronous method call can also be referred to as an asynchronous method call (AMI).

The asynchronous method differs from the synchronous method in the way in which it returns from the call. While an asynchronous method call returns immediately and allows the calling program to perform other operations, synchronous method calls wait for the method to complete before continuing with program flow.

The .NET framework has built-in asynchronous infrastructure so that any method can be called asynchronously without changing the code.

The .NET Framework provides two design patterns for implementing the asynchronous method that asynchronous delegates (IASyncResult objects) and events use. The asynchronous delegate pattern is more complex and offers flexibility, making it suitable for various complex programming models. The event-based model is simple and should be used in most cases.

In the asynchronous delegate pattern, a delegate object uses two methods: BeginInvoke and EndInvoke. BeginInvoke has a list of parameters similar to the wrapped function, along with two additional optional parameters; It returns the IAsyncResult object. EndInvoke returns two parameters (out and ref type) along with the IAsyncResult object. BeginInvoke is used to initiate the asynchronous call, while EndInvoke is used to get the results of the asynchronous call.

Event-based asynchronous patterns use a class with one or more methods called MethodNameAsync that have corresponding synchronous versions that run on the current thread. Event-based patterns can also contain a MethodNameCompleted method and a MethodNameAsyncCancel method. This pattern allows the class to communicate with outstanding asynchronous operations using the delegate event model.

Here are some tips about asynchronous methods:

Asynchronous methods must be avoided for high parallelism

Care should be taken when passing common object references

EndXXX (called at the end of an asynchronous operation) must be called to throw exceptions again and avoid errors

If all exception objects are caught and saved in the asynchronous method, it can be thrown again during the EndXXX call

User interface controls that initiate lengthy asynchronous operations must be disabled if they are only needed for this purpose

Asynchronous methods must be implemented with an understanding of multithreading and where they prove to be more efficient than using synchronous methods.