Updating screen with messages from a thread that raises events (ASP.NET)

Question

I have a very long running process that I start in a thread. This raises events with messages to say what it is doing.

How can I update a label on screen with these messages? (The label is in an update panel if that makes it easier).

If this is not possible, is there a better way you can suggest?

Answer 1

Once the page request has completed the server has no explicit knowledge of, or connection to, the requesting browser so you are unable to easily push a response to the user. The easiest way would be to persist the messages in some way using an identifier and then expose the messages via a service or CallBack function, you could use a Ajax timer to make calls to the service and update the UI accordingly.

Answer 2

Yes, you can. Create a method that will have a parameter (message string to be shown). Like:

private void SetLabelText(string message)
{
            if (label.InvokeRequired)
            {
                Invoke(new MethodInvoker(() => SetLabelText(message)
                           ));
            }
            else
            {
                label.Text = message;
            }
}

Use this method in your event handler.

Answer 3

使用背景工，更新UI 链接文本非常有用