Can You Await Asynchronous Methods Inside a Constructor?

Deep dive into asynchronous calls in constructors

In programming, asynchronous methods allow operations to be executed concurrently without blocking the main thread. A common question is: Can an asynchronous method be called directly from the constructor? This article will delve into the details of this issue and provide a comprehensive explanation.

Asynchronicity in constructors

While performing asynchronous operations in a constructor may seem convenient, it is important to understand its limitations. In C#, constructors are synchronous by default, which means they execute in a linear fashion and cannot wait for asynchronous tasks to complete. Attempting to call an async method directly in the constructor will result in an error.

Alternative methods

In order to achieve asynchronicity in the constructor, several alternatives can be used. One approach is to use asynchronous data binding, allowing the UI to automatically update when data is available. Another strategy is to defer using the await keyword, where the constructor simply starts the asynchronous operation and waits for it to complete later after the UI has been initialized.

Processing LongListView data filling

In the provided code snippet, the issue with the LongListView being empty stems from trying to populate it with data that is not yet available. Since the getWritings() method is asynchronous, it takes time to get and process the JSON data. To solve this problem, a two-step approach is recommended:

1. In the constructor, start the getWritings() method asynchronously and set the LongListView's data source to a placeholder value or an empty list.
2. getWritings() After the method is completed, update the data source of LongListView with the obtained data. This ensures that the UI is initialized while the asynchronous data retrieval is taking place.

Conclusion

Asynchronous operations should be carefully designed and integrated into the constructor to avoid blocking the UI thread. The alternatives provided provide efficient ways to achieve asynchronicity in constructors while maintaining responsiveness and data integrity.

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