下载并在窗口中显示的图像8
问题描述:
我有用于从Web服务器下载的图像下面的代码:下载并在窗口中显示的图像8
private async void Test_Click(object sender, RoutedEventArgs e)
{
HttpClient httpClient = new HttpClient();
HttpRequestMessage request = new HttpRequestMessage(
HttpMethod.Get, "http://www.reignofcomputer.com/imgdump/sample.png");
HttpResponseMessage response = await httpClient.SendAsync(request,
HttpCompletionOption.ResponseHeadersRead);
var imageFile = await ApplicationData.Current.LocalFolder.CreateFileAsync(
"sample.png", CreationCollisionOption.ReplaceExisting);
var fs = await imageFile.OpenAsync(FileAccessMode.ReadWrite);
DataWriter writer = new DataWriter(fs.GetOutputStreamAt(0));
writer.WriteBytes(await response.Content.ReadAsByteArrayAsync());
await writer.StoreAsync();
writer.DetachStream();
await fs.FlushAsync();
displayImage();
}
private void displayImage()
{
image1.Source = new BitmapImage(
new Uri("ms-appdata:///local/sample.png", UriKind.Absolute));
}
当我运行代码,图像无法显示,尽管出现在文件夹中(在
C:\用户\用户\应用程序数据\本地\套餐\ XXXXX \ LocalState)。
如果我再次运行它,我得到UnauthorizedAccessException was unhandled by user code
,Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))
在CreateFileAsync
。
任何想法?
答
下面是下载的图像,并将其显示在应用程序的背景应用程序的工作示例:
http://laurencemoroney.azurewebsites.net/?p=247
async void doLoadBG()
{
System.Xml.Linq.XDocument xmlDoc = XDocument.Load(
"http://www.bing.com/HPImageArchive.aspx?format=xml&idx=0&n=1&mkt=en-US");
IEnumerable<string> strTest = from node in xmlDoc.Descendants("url")
select node.Value;
string strURL = "http://www.bing.com" + strTest.First();
Uri source = new Uri(strURL);
StorageFile destinationFile;
try
{
destinationFile = await ApplicationData.Current.LocalFolder
.CreateFileAsync(
"downloadimage.jpg", CreationCollisionOption.GenerateUniqueName);
}
catch (FileNotFoundException ex)
{
return;
}
BackgroundDownloader downloader = new BackgroundDownloader();
DownloadOperation download =
downloader.CreateDownload(source, destinationFile);
await download.StartAsync();
ResponseInformation response = download.GetResponseInformation();
Uri imageUri;
BitmapImage image = null;
if (Uri.TryCreate(destinationFile.Path, UriKind.RelativeOrAbsolute,
out imageUri))
{
image = new BitmapImage(imageUri);
}
imgBrush.ImageSource = image;
}
答
如果你不想下载的图片,你可以这样做:
private void displayImage()
{
image1.Source = new BitmapImage(
new Uri("http://www.reignofcomputer.com/imgdump/sample.png"));
}
这是否帮助?
+0
sample.png实际上将被替换为动态图像,所以我需要每次都下载一个新的。 – ReignOfComputer 2013-05-01 15:29:58
可能是其中之一“是它插好”的答案,但你有权限设置正确的文件夹? – AngryDuck 2013-05-01 15:23:02