System.IO.FileNotFoundException in delayed function

问题

In my winphone app I have a strange situation where I get a System.IO.FileNotFoundException in code that does nothing related to files.

I have a class that manages delayed function calls:

// Delayed function manager
namespace Test
{
    public static class At
    {
        private readonly static TimerCallback timer = 
            new TimerCallback(At.ExecuteDelayedAction);

        public static void Do(Action action, TimeSpan delay,
            int interval = Timeout.Infinite)
        {
            var secs = Convert.ToInt32(delay.TotalMilliseconds);
            new Timer(timer, action, secs, interval);
        }

        public static void Do(Action action, int delay, 
            int interval = Timeout.Infinite)
        {
            Do(action, TimeSpan.FromMilliseconds(delay), interval);
        }

        public static void Do(Action action, DateTime dueTime, 
            int interval = Timeout.Infinite)
        {
            if (dueTime < DateTime.Now) return;
            else Do(action, dueTime - DateTime.Now, interval);
        }

        private static void ExecuteDelayedAction(object o)
        {
            (o as Action).Invoke();
        }
    }
}

And a class that manages ProgressIndicator state:

namespace Test
{
    public class Indicator
    {
        public DependencyObject ThePage;
        public ProgressIndicator Progressor;
        public Indicator(DependencyObject page)
        {
            ThePage = page;
            Progressor = new ProgressIndicator();
            SystemTray.SetProgressIndicator(ThePage, Progressor);
        }

        // If set(true) then set(false) in one second to remove ProgressIndicator
        public void set(bool isOn)
        {
            Progressor.IsIndeterminate = Progressor.IsVisible = isOn; // Exception happens on this line
            if (isOn) At.Do(delegate { this.set(false); }, 1000);
        }
    }
}

When I try to run set(true) method in code I get the following exception:

An exception of type 'System.IO.FileNotFoundException' occurred in mscorlib.ni.dll and wasn't handled before a managed/native boundary
A first chance exception of type 'System.UnauthorizedAccessException' occurred in System.Windows.ni.dll

Why is this happening and how can this be fixed?

回答1:

Looks like your actual problem is permissions, the FileNotFound exception is probably happening as a result of not being able to read the file location directory.

I don't have any experience with Windows Phone development, however, I assume wherever System.Windows.ni.dll is resided requires higher permissions than what you are running your app under.

Update

Based on your call stack error message - "Invalid cross-thread access", the problem is your attempting to access/update a GUI component from another thread which isn't the UI thread. Try changing your code to:

Deployment.Current.Dispatcher.BeginInvoke(()=>
{ 
    Progressor.IsIndeterminate = Progressor.IsVisible = isOn;
    if (isOn) 
        At.Do(delegate { this.set(false); }, 1000);
}

});

来源：https://stackoverflow.com/questions/13972669/system-io-filenotfoundexception-in-delayed-function

标签

exception

timer

timeout

windows-phone-8