C# UWP ObservableCollection,来自webservice的数据未更新GUI
我正在listview上使用ObservableCollection。ObservaleCollection使用异步方法从web服务正确获取数据,然后对其进行解析,并使用NewsProxyParser(string thing,out ObservaleCollection newsList)方法上的Add方法填充ObservaleCollection,但我无法使用绑定的ObservaleCollection更新GUI 我是UWP新手,所以我假设异步方法运行在GUI支持的另一个线程上。如何正确地进行绑定以使用从web服务获取的数据更新GUI 我的XAML:C# UWP ObservableCollection,来自webservice的数据未更新GUI,c#,win-universal-app,observablecollection,windows-10-universal,C#,Win Universal App,Observablecollection,Windows 10 Universal,我正在listview上使用ObservableCollection。ObservaleCollection使用异步方法从web服务正确获取数据,然后对其进行解析,并使用NewsProxyParser(string thing,out ObservaleCollection newsList)方法上的Add方法填充ObservaleCollection,但我无法使用绑定的ObservaleCollection更新GUI 我是UWP新手,所以我假设异步方法运行在GUI支持的另一个线程上。如何正确地
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<ListView Name="ListViewNews" ItemsSource="{x:Bind NewsCollection, Mode=OneWay}" IsItemClickEnabled="True" ItemClick="ListView_ItemClick">
<ListView.ItemTemplate>
<DataTemplate x:DataType="data:News">
<RelativePanel Margin="0,16" >
<Image Name="x:Thumb" Source="{x:Bind thumbnailUrl}" Width="96" Height="96" RelativePanel.AlignLeftWithPanel="True" Margin="0,0,16,0"></Image>
<TextBlock Name="x:Title" Text="{x:Bind title}" FontSize="22" FontWeight="Bold" RelativePanel.RightOf="x:Thumb"></TextBlock>
<TextBlock Name="x:Date" Text="{x:Bind dateString}" FontSize="12" FontWeight="Light" Foreground="Gray" RelativePanel.RightOf="x:Thumb" RelativePanel.Below="x:Title"></TextBlock>
<TextBlock Name="x:Text" Text="{x:Bind newsText}" Foreground="Gray" RelativePanel.RightOf="x:Thumb" RelativePanel.Below="x:Date"></TextBlock>
</RelativePanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</Grid>
政务司司长:
public sealed partial class NewsPage : Page
{
private ObservableCollection<News> NewsCollection;
public NewsPage()
{
NewsRequest();
this.InitializeComponent();
}
private async void NewsRequest()
{
//Fetch News from web
string response = await NewsProxy.GetNews("TokenX");
//Parse News to add to NewsCollection
bool success = NewsProxy.NewsProxyParser(response, out NewsCollection);
// success is true and NewsCollection has new updated values
if (success)
{
News n = new News();
n.title = "Just to trigger collectionchanged";
n.newsText = "dadada";
n.order = 1;
NewsCollection.Add(n);
Debug.WriteLine("Still No GUI updated!!!");
}
}
}
公共密封部分类新闻页:第页
{
私人收集新闻;
公共新闻页()
{
NewsRequest();
this.InitializeComponent();
}
私有异步void newrequest()
{
//从网上获取新闻
string response=await NewsProxy.GetNews(“TokenX”);
//解析要添加到新闻集合的新闻
bool success=NewsProxy.NewsProxyParser(响应,输出新闻集合);
//success为true,NewsCollection具有新的更新值
如果(成功)
{
新闻n=新新闻();
n、 title=“只是为了触发collectionchanged”;
n、 newsText=“dadada”;
n、 顺序=1;
添加(n);
WriteLine(“仍然没有更新GUI!!!”;
}
}
}
ObservableCollection
仅通知集合更改,例如添加和删除项目。只要替换整个集合,就需要将newscolection
设置为依赖项属性,以通知XAML UI有关更改的信息
public ObservableCollection<News> NewsCollection
{
get { return (ObservableCollection<News>)GetValue(NewsCollectionProperty); }
set { SetValue(NewsCollectionProperty, value); }
}
public static readonly DependencyProperty NewsCollectionProperty =
DependencyProperty.Register("NewsCollection", typeof(ObservableCollection<News>), typeof(NewsPage), new PropertyMetadata(null));
private async void NewsRequest()
{
//Fetch News from web
string response = await NewsProxy.GetNews("TokenX");
//Parse News to add to NewsCollection
ObservableCollection<News> newsCollection;
bool success = NewsProxy.NewsProxyParser(response, out newsCollection);
NewsCollection = newsCollection;
// success is true and NewsCollection has new updated values
if (success)
{
News n = new News();
n.title = "Just to trigger collectionchanged";
n.newsText = "dadada";
n.order = 1;
NewsCollection.Add(n);
Debug.WriteLine("Still No GUI updated!!!");
}
}
public-observeCollection新闻集合
{
get{return(ObservableCollection)GetValue(NewsCollectionProperty);}
set{SetValue(newscolectionproperty,value);}
}
公共静态只读从属属性NewsCollectionProperty=
DependencyProperty.Register(“NewsCollection”、typeof(ObservableCollection)、typeof(NewsPage)、new PropertyMetadata(null));
私有异步void newrequest()
{
//从网上获取新闻
string response=await NewsProxy.GetNews(“TokenX”);
//解析要添加到新闻集合的新闻
可观察的收集新闻;
bool success=NewsProxy.NewsProxyParser(响应,输出新闻集合);
新闻收集=新闻收集;
//success为true,NewsCollection具有新的更新值
如果(成功)
{
新闻n=新新闻();
n、 title=“只是为了触发collectionchanged”;
n、 newsText=“dadada”;
n、 顺序=1;
添加(n);
WriteLine(“仍然没有更新GUI!!!”;
}
}