updating a asp.net 4.0 webform ui controls from a Task

Question

Hi have asp.net 4.0 webfrom with UpdatePanel and AjaxControlsToolKit.

Inside this web from I have a Task who runs on a generic list of recipients and send them the mail while also saving it as a pdf file in a files server and uploading it via web service to the organization ERP system.

I want to catch/log errors during the task process and in the end to show them to the user and let him run the process on them again.

Task sendMailTask =
Task.Factory.StartNew((stateObj) =>
{
// some code with for loop on a collection of receipents who call another function which try to save the file using the web service in the ERP.
},2000);
try
{
if (!sendMailTask.IsCanceled && !sendMailTask.IsFaulted)
{
StatusMessagesContainerModalDialog.Attributes["class"] = "modal-content alert-success";
StatusMessagesContainer.CssClass = "text-center";
Status.Text = "Your email was sent";
StatusMessagesModalPopup.Show();
}
}
catch (AggregateException ex)
{
StatusMessagesContainerModalDialog.Attributes["class"] = "modal-content alert-warning";
StatusMessagesContainer.CssClass = "text-center";
Status.Text = "Error occured";
StatusMessagesModalPopup.Show();
}

 

How can update the ui?

Right now the user get a message that the email was sent immediately before the task completed and when i try to update the ui from the task itself even when using ContinueWith nothing happens in the ui tread and the user does not see the data i want him to see.