拒绝访问：未经授权的ExCeption

Question

我的项目中发生以下错误，有人能告诉我如何解决此异常吗？

访问被拒绝。（Windows手机8.1中的HRESULT异常：0x80070005（E_ACCESSDENIED））。

我有这个代码：

using (IRandomAccessStream readStream = await file.OpenAsync(FileAccessMode.Read))




        StorageFile file = usertoken ;
        try
        {
            if (file != null)
            {
                using (IRandomAccessStream readStream = await file.OpenAsync(FileAccessMode.Read))
                {
                    using (DataReader dataReader = new DataReader(readStream))
                    {
                        UInt64 size = readStream.Size;

                        UInt32 numBytesLoaded = await dataReader.LoadAsync((UInt32)size);
                        string fileContent = dataReader.ReadString(numBytesLoaded);
                        return (bool)true;
                        // NotifyUser(String.Format("The following text was read from '{0}' using a stream:{1}{2}", file.Name, Environment.NewLine, fileContent), NotifyType.StatusMessage);

                    }
                }
            }
            else
            {
                return (bool)false;
            }
        }
        catch
        {
            return (bool)false;
        }