Asynchronous Download of Information

When you need to get information for a property from elsewhere on a network or from an external source on the Internet, the amount of time it takes to download such information might be a long time to expect the user to wait.

In such cases, you'll want to use asynchronous downloading of property information. An asynchronous download can happen in the background of the rest of your application, and users can have use of your application while the download happens. The basic steps of an asynchronous download are

1. Begin to download information. The application requests data with the AsyncRead method.

2. Information is being downloaded. The download happens in the background. During this time, the application is free to do other things. If the users (or the application) change their minds about downloading the data, you can call the CancelAsyncRead method during this time.

3. Information has finished downloading. The application receives an AsyncReadComplete event, notifying it that the download has finished.

You can write code in the AsyncReadComplete event to handle the downloaded data.

The following sections discuss these features of the asynchronous download.

1. Starting the Download With the AsyncRead Method

2. Stopping the Download With the CancelAsyncRead Method

3. Reacting to the Download Completion With the AsyncReadComplete Event