Question

在我的winphone应用程序中，我遇到一个奇怪的情况，我在代码中得到System.IO.FileNotFoundException，与文件没有任何关系。

我有一个管理延迟函数调用的类：

// 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();
        }
    }
}

管理ProgressIndicator状态的类：

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);
        }
    }
}

当我尝试在代码中运行set(true)方法时，我得到以下异常：

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

为什么会发生这种情况？如何解决？

Answer 1

看起来您的实际问题是权限，FileNotFound异常可能由于无法读取文件位置目录而发生。

我对Windows Phone开发没有任何经验，但是，我假设System.Windows.ni.dll所在的位置需要比您运行应用程序时更高的权限。

<强>更新

根据您的调用堆栈错误消息 - “无效的跨线程访问”，问题是您尝试从另一个不是UI线程的线程访问/更新GUI组件。尝试将代码更改为：

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

});

延迟函数中的System.IO.FileNotFoundException

1 个答案: