‘BackgroundWorker Component’ is used to do long-running tasks in the background while the application runs in the foreground. When the background task is going on, the application can still look for the user events and replies to them. Generally when the application is busy doing a long-running task, users of the application cannot reach out with the UI items. This is because there is only one thread which is busy dealing with the long-running task. Here, we will create a sample that counts vowels of the textual content given in a text box. To make that as a long-running task, we will ask the execution to sleep for 50 milliseconds after processing a single character. Using this sample task, we will create our example and study the C# BackgroundWorker Component.