HttpClient.GetBufferAsync() 无法编译

Question

我有一个程序，我想在其中从 Internet 下载图像。我遵循了本教程：How to download and store an image using Windows.Web.Http?。

这是我的源代码：

Uri uri = new Uri(CoverImage);
string filename = BookNameTextBox.Text + ".jpg";

StorageFile destinationFile = await ApplicationData.Current.LocalFolder.CreateFileAsync(filename);

HttpClient client = new HttpClient();

var buffer = await client.GetBufferAsync(uri);

StorageFile photo = await ApplicationData.Current.LocalFolder.GetFileAsync(CoverImage);

程序无法编译。它说，“HttpClient 不包含 'GetBufferAsync' 的定义”。在谷歌搜索时，我发现这篇文章https://docs.microsoft.com/en-us/uwp/api/windows.web.http.httpclient.getbufferasync 根据该方法存在。我不知道该怎么办。

具有讽刺意味的是，我实际上在另一个文件中使用了 HttpClient，它工作正常。这是那部分：

var http = new HttpClient();

string url = "https://www.googleapis.com/books/v1/volumes?q=" + title.Replace(' ', '+') + "&fields = items(volumeInfo(title, authors, publisher)), items/";
var response = await http.GetAsync(url);
var result = await response.Content.ReadAsStringAsync();

Answer 1

确保您使用Windows.Web.Http.HttpClient 类（而不是System.Net.Http.HttpClient 类）：

Windows.Web.Http.HttpClient client = new Windows.Web.Http.HttpClient();