UI Thread blocked in C# WPF App during Async Download

Question

I have the following basic WPF app, where I want the content displayed in the text box. However, when I click on the button, the UI thread seems to be blocking. I am not sure wh

Answer 1

This shouldn't block the UI thread, and the technique is correct.

However, just because a method is Async, and returns a Task<T>, doesn't guarantee that the entire method (or any of it) will run asynchronously.

In the case of WebClient, the control won't return to the caller until after the request has been completely prepared and started. With WebClient, I believe the URI preparation, including all of the DNS lookups, can happen synchronously and is required before the asynchronous portion (the actual request) begins, which can cause a delay before the request returns.