XAMARIN窗体-检查文件是否存在于环境中。

在Xamarin表单中,如何检查Environment.SpecialFolder.DesktopDirectory是否包含文件?

我用下面的方法从Azure存储中下载图像,并在页面上显示它们,它运行良好,但我只想在没有文件的情况下这样做。

_activityIndicator.IsRunning = true;
            var imgPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory), "");
            var blobList = await BlobStorageService.GetBlobs<CloudBlockBlob>("images");

            foreach (CloudBlockBlob b in blobList)
            {
                Image _image = new Image();
                imgPath = imgPath + b.Name;
                await b.DownloadToFileAsync(imgPath, FileMode.Create);

                StackLayout s = new StackLayout();
                _title.Text = b.Name;
                _image.Source = imgPath; 
                s.Children.Add(_title);
                s.Children.Add(_image);
                iStack.Children.Add(s);
            }