/// <summary>
/// Creates or loads the state for this task.
/// </summary>
/// <param name="task">The task to create or load state for.</param>
/// <returns></returns>
protected State GetState(ITask task)
{
State _state = null;
Guid taskId = Guid.Empty;
// THREE-WAY DECISION:
// 1) no ITask object--assume new Task, create new TaskID, create new State
// 2) ITask object, but no valid TaskID--assume new Task, create new State
// 3) ITask object, valid TaskID--assume known Task, retrieve known State
//
// CASE (1):
// if incoming ITask is null, we KNOW this is a new Task. Act appropriately--create new Task/State
if (null == task)
{
_state = CreateState();
taskId = _state.TaskId;
}
else
{
// ask the incoming ITask if it has a TaskID already.
// this would mean the application has already hooked up a Task ID to whatever representation it uses...
// for example, correlating TaskID to windows logon
taskId = task.Get();
_state = GetState(taskId);
if (Guid.Empty == taskId)
{
// tell the taskObject (which is our sink back into client application) about the new TaskID
task.Create(_state.TaskId);
}
}
return(_state);
}
//----< wrapper runs long task asynchronously >----------------------
Task longTaskWrapper()
{
// create instance of native task
ITask rTask = ITask.Create();
// hook up callback if not done already
if (rTask.callback == null)
{
rTask.callback = new ITask.EventCallBack(this.updateStatus);
}
// run task asynchronously
Task task = Task.Run(() => rTask.run(Dispatcher));
return(task);
}
//----< Run long task synchronously on UI thread >-------------------
private void SynchButton_Click(object sender, RoutedEventArgs e)
{
disableButtons();
// Force UI to update. Without this buttons stay enabled.
Dispatcher.Invoke(() => InvalidateVisual(), System.Windows.Threading.DispatcherPriority.Render);
// create native task instance
ITask rTask = ITask.Create();
// no point in sending callbacks - UI thread isn't listening
// rTask.callback = new ITask.EventCallBack(this.updateStatus);
rTask.run(Dispatcher);
// Refresh UI
enableButtons();
}
public void Create()
{
Task.Create();
}