GridView沒有在uwp中顯示記錄

Question

我正在開發一個uwp應用程序。 我不是在這種情況下關注MVVM。 我正在從url獲取json數據並使用Newtonsoft解析它並希望將其綁定到DataGrid控件。 問題是數據網格根本沒有出現。 在頁面加載時，我使用Dispatcher填充collectionviewsource並綁定到GridView。 但沒有幫助。 請幫忙。

XAML：

<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="*"></RowDefinition>
        </Grid.RowDefinitions>
        <StackPanel Orientation="Horizontal" Grid.Row="0" Margin="20">
            <TextBlock Text="Search:"></TextBlock>
            <TextBox Height="30" Width="140" Margin="20,0,0,0"></TextBox>
        </StackPanel>

        <GridView Grid.Row="1" ItemsSource="{Binding viewSource.View}" Height="500" SelectionMode="Single" Width="Auto">
            <GridView.ItemTemplate>
                <DataTemplate>
                    <StackPanel>
                        <TextBlock Text="{Binding recordID}"></TextBlock>
                        <TextBlock Text="{Binding allergy_name}"></TextBlock>
                        <TextBlock Text="{Binding reaction}"></TextBlock>
                        <TextBlock Text="{Binding allergy_date}"></TextBlock>
                        <TextBlock Text="{Binding severity}"></TextBlock>
                        <TextBlock Text="{Binding status}"></TextBlock>
                    </StackPanel>
                </DataTemplate>
            </GridView.ItemTemplate>
        </GridView>
</Grid>

這是我的XAML.cs

TwoFactor factor;
public CollectionViewSource viewSource { get; set; }
        private List<AllergyRecord> _allergyrecords;
        public List<AllergyRecord> AllAllergies
        {
            get
            {
                return _allergyrecords;
            }
            set { _allergyrecords = value; }
        }
        public AddAllergy()
        {
            this.InitializeComponent(); 
            this.DataContext = this;
            viewSource = new CollectionViewSource();
        }

        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            base.OnNavigatedTo(e);
            factor = (TwoFactor)e.Parameter;
        }

        public async Task<string> jsonResult(string url)
        {
            string data;
            var client = new HttpClient();
            HttpResponseMessage response = await client.GetAsync(url);
            using (HttpContent content = response.Content)
            {
                data = await content.ReadAsStringAsync();
            }

            return data;
        }



        private async void Page_Loaded(object sender, RoutedEventArgs e)
        {
            AllAllergies = new List<AllergyRecord>();
            string json = await jsonResult("http://ec2-54-83-191-130.compute-1.amazonaws.com:8080/Sanjeevani/rest/SV/GetAllergy/" + factor.Passcode);
            RootObject data = JsonConvert.DeserializeObject<RootObject>(json);

            foreach (var item in data.AllergyRecords)
            {
                AllAllergies.Add(item);
            }
            Windows.ApplicationModel.Core.CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync(CoreDispatcherPriority.Normal,
() =>
{
    viewSource.Source = AllAllergies;
});

        }
    }

這是我的Root Object類。

public class AllergyRecord
    {
        public string allergy_date { get; set; }
        public string allergy_name { get; set; }
        public string reaction { get; set; }
        public string recordID { get; set; }
        public string severity { get; set; }
        public string status { get; set; }
    }

    public class RootObject
    {
        public List<AllergyRecord> AllergyRecords { get; set; }
        public string ForceLogOn { get; set; }
        public string returnCode { get; set; }
    }

Answer 1

好的，這是我做的步驟。 萬一它可以幫助某人。 首先是我對gridview部分的XAML更改。

<GridView x:Name="grdData" Grid.Row="1" ItemsSource="{x:Bind AllAllergies}" Height="300" SelectionMode="Single" Width="Auto" Background="AliceBlue">
            <GridView.ItemTemplate>
                <DataTemplate x:DataType="local:AllergyRecord">
                    <StackPanel HorizontalAlignment="Center" Orientation="Horizontal">
                        <TextBlock Text="{x:Bind recordID}"></TextBlock>
                        <TextBlock Text="{x:Bind allergy_name}"></TextBlock>
                        <TextBlock Text="{x:Bind reaction}"></TextBlock>
                        <TextBlock Text="{x:Bind allergy_date}"></TextBlock>
                        <TextBlock Text="{x:Bind severity}"></TextBlock>
                        <TextBlock Text="{x:Bind status}"></TextBlock>
                    </StackPanel>
                </DataTemplate>
            </GridView.ItemTemplate>
        </GridView>

我在XAML.cs中所做的改變是

注釋掉了.DataContext =在初始化組件下面的這一行全部在一起，在異步頁面加載的最后我只是說了這個.Bindings.Update（）; 作為最后一行，它的工作原理。 這是同一類型的問題和答案。 數據未顯示（C＃UWP）

Answer 2

既然你提到了MVVM，我會建議一個MVVM模式的答案。

首先，您需要將Web調用移動到ViewModel類。 所以它的外觀如下。

public class AllAllergiesViewModel
{
    public RootObject rootObject { get; set; }
    public async Task GetAllAllergies()
    {
        string json = await jsonResult("http://ec2-54-83-191-130.compute-1.amazonaws.com:8080/Sanjeevani/rest/SV/GetAllergy/" + factor.Passcode);
        this.rootObject = JsonConvert.DeserializeObject<RootObject>(json);
    }

    internal async Task<string> jsonResult(string url)
    {
        string data;
        var client = new HttpClient();
        HttpResponseMessage response = await client.GetAsync(url);
        using (HttpContent content = response.Content)
        {
            data = await content.ReadAsStringAsync();
        }
        return data;
    }
}

您的RootObject將如下所示。

public class RootObject
{
    public ObservableCollection<AllergyRecord> AllergyRecords { get; set; }
    public string ForceLogOn { get; set; }
    public string returnCode { get; set; }
}

在MainPage_Loaded ，您可以使用如下所示的DataContext 。

private async void MainPage_Loaded(object sender, RoutedEventArgs e)
{
    var viewModel = new AllAllergiesViewModel();
    grdData.DataContext = viewModel;
    await viewModel.GetAllAllergies();
}

而你的XAML將是

<GridView Grid.Row="1" ItemsSource="{Binding AllergyRecords}" Height="500" SelectionMode="Single" Width="Auto" x:Name="grdData">
    <GridView.ItemTemplate>
        <DataTemplate>
            <StackPanel>
                <TextBlock Text="{Binding recordID}"></TextBlock>
                <TextBlock Text="{Binding allergy_name}"></TextBlock>
                <TextBlock Text="{Binding reaction}"></TextBlock>
                <TextBlock Text="{Binding allergy_date}"></TextBlock>
                <TextBlock Text="{Binding severity}"></TextBlock>
                <TextBlock Text="{Binding status}"></TextBlock>
            </StackPanel>
        </DataTemplate>
    </GridView.ItemTemplate>
</GridView>