C# 将可观察集合绑定到GridView
我的UWP需要有一个收藏夹页面,允许用户在页面上重新排序和保存数据。最初,我的数据来自一个大型JSON文件,该文件使用Newtonsoft的JSON.net进行反序列化,并存储在一个字典中,然后填充公共ObservableCollection 这就是我现在迷路的地方,将ObservableCollection设置为DataContext,然后在XAML代码中使用数据作为绑定,用每个项目所需的所有标题、副标题和图像填充GridView。 理论上,这应该是可行的,但在我的测试和测试中,页面仍然是空白的,而所有幕后的C#代码似乎都应该填充 我不知道为什么这一页没有被填满,我要求助于你们所有人的集体帮助 附言:我真的不在乎这个代码的整洁,我只是想让它工作起来C# 将可观察集合绑定到GridView,c#,uwp,observablecollection,uwp-xaml,C#,Uwp,Observablecollection,Uwp Xaml,我的UWP需要有一个收藏夹页面,允许用户在页面上重新排序和保存数据。最初,我的数据来自一个大型JSON文件,该文件使用Newtonsoft的JSON.net进行反序列化,并存储在一个字典中,然后填充公共ObservableCollection 这就是我现在迷路的地方,将ObservableCollection设置为DataContext,然后在XAML代码中使用数据作为绑定,用每个项目所需的所有标题、副标题和图像填充GridView。 理论上,这应该是可行的,但在我的测试和测试中,页面仍然是空白
XAML文件
<Page
x:Name="pageRoot"
x:Class="Melbourne_Getaway.FavouritesPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Melbourne_Getaway"
xmlns:data="using:Melbourne_Getaway.Data"
xmlns:common="using:Melbourne_Getaway.Common"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Page.Resources>
<x:String x:Key="AppName">Favourites</x:String>
</Page.Resources>
<!--
This grid acts as a root panel for the page that defines two rows:
* Row 0 contains the back button and page title
* Row 1 contains the rest of the page layout
-->
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Grid.ChildrenTransitions>
<TransitionCollection>
<EntranceThemeTransition />
</TransitionCollection>
</Grid.ChildrenTransitions>
<Grid.RowDefinitions>
<RowDefinition Height="140" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<GridView
x:Name="itemGridView"
AutomationProperties.AutomationId="ItemsGridView"
AutomationProperties.Name="Items"
TabIndex="1"
Grid.RowSpan="2"
Padding="60,136,116,46"
SelectionMode="None"
IsSwipeEnabled="false"
CanReorderItems="True"
CanDragItems="True"
AllowDrop="True"
ItemsSource="{Binding Items}">
<GridView.ItemTemplate>
<DataTemplate>
<Grid HorizontalAlignment="Left" Width="250" Height="107">
<Border Background="{ThemeResource ListViewItemPlaceholderBackgroundThemeBrush}">
<Image Source="{Binding ImagePath}" Stretch="UniformToFill" AutomationProperties.Name="{Binding Title}" />
</Border>
<StackPanel VerticalAlignment="Bottom" Background="{ThemeResource ListViewItemOverlayBackgroundThemeBrush}">
<TextBlock Text="{Binding Title}" Foreground="{ThemeResource ListViewItemOverlayForegroundThemeBrush}" Style="{StaticResource BaseTextBlockStyle}" Height="30" Margin="15,0,15,0" FontWeight="SemiBold" />
<TextBlock Text="{Binding Group}" Foreground="{ThemeResource ListViewItemOverlaySecondaryForegroundThemeBrush}" Style="{StaticResource BaseTextBlockStyle}" TextWrapping="NoWrap" Margin="15,-15,15,10" FontSize="12" />
</StackPanel>
</Grid>
</DataTemplate>
</GridView.ItemTemplate>
</GridView>
<!-- Back button and page title -->
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="120" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Button x:Name="backButton" Margin="39,59,39,0" Command="{Binding NavigationHelper.GoBackCommand, ElementName=pageRoot}"
Style="{StaticResource NavigationBackButtonNormalStyle}"
VerticalAlignment="Top"
AutomationProperties.Name="Back"
AutomationProperties.AutomationId="BackButton"
AutomationProperties.ItemType="Navigation Button" />
<TextBlock x:Name="pageTitle" Text="{StaticResource AppName}" Style="{StaticResource HeaderTextBlockStyle}" Grid.Column="1"
IsHitTestVisible="false" TextWrapping="NoWrap" VerticalAlignment="Bottom" Margin="0,0,30,40" />
</Grid>
</Grid>
using Melbourne_Getaway.Common;
using Melbourne_Getaway.Data;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using Windows.Storage;
using Windows.UI.Popups;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;
namespace Melbourne_Getaway
{
public sealed partial class FavouritesPage : Page
{
public ObservableCollection<ItemData> Items { get; set; }
private ObservableDictionary defaultViewModel = new ObservableDictionary();
private NavigationHelper navigationHelper;
private RootObject jsonLines;
private StorageFile fileFavourites;
private Dictionary<string, ItemData> ItemData = new Dictionary<string, ItemData>();
public FavouritesPage()
{
loadJson();
getFavFile();
this.InitializeComponent();
this.navigationHelper = new NavigationHelper(this);
this.navigationHelper.LoadState += navigationHelper_LoadState;
}
private void setupObservableCollection()
{
Items = new ObservableCollection<ItemData>(ItemData.Values);
DataContext = Items;
}
private async void loadJson()
{
var file = await StorageFile.GetFileFromApplicationUriAsync(new Uri("ms-appx:///DataModel/SampleData.json"));
string lines = await FileIO.ReadTextAsync(file);
jsonLines = JsonConvert.DeserializeObject<RootObject>(lines);
feedItems();
}
private async void getFavFile()
{
Windows.Storage.StorageFolder storageFolder = Windows.Storage.ApplicationData.Current.LocalFolder;
fileFavourites = await storageFolder.GetFileAsync("MelbGetaway.fav");
}
private async void feedItems()
{
if (await FileIO.ReadTextAsync(fileFavourites) != "")
{
foreach (var line in await FileIO.ReadLinesAsync(fileFavourites))
{
foreach (var Group in jsonLines.Groups)
{
foreach (var Item in Group.Items)
{
if (Item.UniqueId == line)
{
var storage = new ItemData()
{
Title = Item.Title,
UniqueID = Item.UniqueId,
ImagePath = Item.ImagePath,
Group = Group.Title
};
ItemData.Add(storage.UniqueID, storage);
}
}
}
}
}
else
{//should only execute if favourites file is empty, first time use?
foreach (var Group in jsonLines.Groups)
{
foreach (var Item in Group.Items)
{
var storage = new ItemData()
{
Title = Item.Title,
UniqueID = Item.UniqueId,
ImagePath = Item.ImagePath,
Group = Group.Title
};
ItemData.Add(storage.UniqueID, storage);
await FileIO.AppendTextAsync(fileFavourites, Item.UniqueId + "\r\n");
}
}
}
setupObservableCollection();
}
public ObservableDictionary DefaultViewModel
{
get { return this.defaultViewModel; }
}
#region NavigationHelper loader
public NavigationHelper NavigationHelper
{
get { return this.navigationHelper; }
}
private async void MessageBox(string Message)
{
MessageDialog dialog = new MessageDialog(Message);
await dialog.ShowAsync();
}
private async void navigationHelper_LoadState(object sender, LoadStateEventArgs e)
{
var sampleDataGroups = await SampleDataSource.GetGroupsAsync();
this.defaultViewModel["Groups"] = sampleDataGroups;
}
#endregion NavigationHelper loader
#region NavigationHelper registration
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
navigationHelper.OnNavigatedFrom(e);
}
protected override void OnNavigatedTo(NavigationEventArgs e)
{
navigationHelper.OnNavigatedTo(e);
}
#endregion NavigationHelper registration
}
public class ItemData
{
public string UniqueID { get; set; }
public string Title { get; set; }
public string Group { get; set; }
public string ImagePath { get; set; }
}
}
宠儿
CS文件
<Page
x:Name="pageRoot"
x:Class="Melbourne_Getaway.FavouritesPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Melbourne_Getaway"
xmlns:data="using:Melbourne_Getaway.Data"
xmlns:common="using:Melbourne_Getaway.Common"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Page.Resources>
<x:String x:Key="AppName">Favourites</x:String>
</Page.Resources>
<!--
This grid acts as a root panel for the page that defines two rows:
* Row 0 contains the back button and page title
* Row 1 contains the rest of the page layout
-->
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Grid.ChildrenTransitions>
<TransitionCollection>
<EntranceThemeTransition />
</TransitionCollection>
</Grid.ChildrenTransitions>
<Grid.RowDefinitions>
<RowDefinition Height="140" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<GridView
x:Name="itemGridView"
AutomationProperties.AutomationId="ItemsGridView"
AutomationProperties.Name="Items"
TabIndex="1"
Grid.RowSpan="2"
Padding="60,136,116,46"
SelectionMode="None"
IsSwipeEnabled="false"
CanReorderItems="True"
CanDragItems="True"
AllowDrop="True"
ItemsSource="{Binding Items}">
<GridView.ItemTemplate>
<DataTemplate>
<Grid HorizontalAlignment="Left" Width="250" Height="107">
<Border Background="{ThemeResource ListViewItemPlaceholderBackgroundThemeBrush}">
<Image Source="{Binding ImagePath}" Stretch="UniformToFill" AutomationProperties.Name="{Binding Title}" />
</Border>
<StackPanel VerticalAlignment="Bottom" Background="{ThemeResource ListViewItemOverlayBackgroundThemeBrush}">
<TextBlock Text="{Binding Title}" Foreground="{ThemeResource ListViewItemOverlayForegroundThemeBrush}" Style="{StaticResource BaseTextBlockStyle}" Height="30" Margin="15,0,15,0" FontWeight="SemiBold" />
<TextBlock Text="{Binding Group}" Foreground="{ThemeResource ListViewItemOverlaySecondaryForegroundThemeBrush}" Style="{StaticResource BaseTextBlockStyle}" TextWrapping="NoWrap" Margin="15,-15,15,10" FontSize="12" />
</StackPanel>
</Grid>
</DataTemplate>
</GridView.ItemTemplate>
</GridView>
<!-- Back button and page title -->
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="120" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Button x:Name="backButton" Margin="39,59,39,0" Command="{Binding NavigationHelper.GoBackCommand, ElementName=pageRoot}"
Style="{StaticResource NavigationBackButtonNormalStyle}"
VerticalAlignment="Top"
AutomationProperties.Name="Back"
AutomationProperties.AutomationId="BackButton"
AutomationProperties.ItemType="Navigation Button" />
<TextBlock x:Name="pageTitle" Text="{StaticResource AppName}" Style="{StaticResource HeaderTextBlockStyle}" Grid.Column="1"
IsHitTestVisible="false" TextWrapping="NoWrap" VerticalAlignment="Bottom" Margin="0,0,30,40" />
</Grid>
</Grid>
using Melbourne_Getaway.Common;
using Melbourne_Getaway.Data;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using Windows.Storage;
using Windows.UI.Popups;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;
namespace Melbourne_Getaway
{
public sealed partial class FavouritesPage : Page
{
public ObservableCollection<ItemData> Items { get; set; }
private ObservableDictionary defaultViewModel = new ObservableDictionary();
private NavigationHelper navigationHelper;
private RootObject jsonLines;
private StorageFile fileFavourites;
private Dictionary<string, ItemData> ItemData = new Dictionary<string, ItemData>();
public FavouritesPage()
{
loadJson();
getFavFile();
this.InitializeComponent();
this.navigationHelper = new NavigationHelper(this);
this.navigationHelper.LoadState += navigationHelper_LoadState;
}
private void setupObservableCollection()
{
Items = new ObservableCollection<ItemData>(ItemData.Values);
DataContext = Items;
}
private async void loadJson()
{
var file = await StorageFile.GetFileFromApplicationUriAsync(new Uri("ms-appx:///DataModel/SampleData.json"));
string lines = await FileIO.ReadTextAsync(file);
jsonLines = JsonConvert.DeserializeObject<RootObject>(lines);
feedItems();
}
private async void getFavFile()
{
Windows.Storage.StorageFolder storageFolder = Windows.Storage.ApplicationData.Current.LocalFolder;
fileFavourites = await storageFolder.GetFileAsync("MelbGetaway.fav");
}
private async void feedItems()
{
if (await FileIO.ReadTextAsync(fileFavourites) != "")
{
foreach (var line in await FileIO.ReadLinesAsync(fileFavourites))
{
foreach (var Group in jsonLines.Groups)
{
foreach (var Item in Group.Items)
{
if (Item.UniqueId == line)
{
var storage = new ItemData()
{
Title = Item.Title,
UniqueID = Item.UniqueId,
ImagePath = Item.ImagePath,
Group = Group.Title
};
ItemData.Add(storage.UniqueID, storage);
}
}
}
}
}
else
{//should only execute if favourites file is empty, first time use?
foreach (var Group in jsonLines.Groups)
{
foreach (var Item in Group.Items)
{
var storage = new ItemData()
{
Title = Item.Title,
UniqueID = Item.UniqueId,
ImagePath = Item.ImagePath,
Group = Group.Title
};
ItemData.Add(storage.UniqueID, storage);
await FileIO.AppendTextAsync(fileFavourites, Item.UniqueId + "\r\n");
}
}
}
setupObservableCollection();
}
public ObservableDictionary DefaultViewModel
{
get { return this.defaultViewModel; }
}
#region NavigationHelper loader
public NavigationHelper NavigationHelper
{
get { return this.navigationHelper; }
}
private async void MessageBox(string Message)
{
MessageDialog dialog = new MessageDialog(Message);
await dialog.ShowAsync();
}
private async void navigationHelper_LoadState(object sender, LoadStateEventArgs e)
{
var sampleDataGroups = await SampleDataSource.GetGroupsAsync();
this.defaultViewModel["Groups"] = sampleDataGroups;
}
#endregion NavigationHelper loader
#region NavigationHelper registration
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
navigationHelper.OnNavigatedFrom(e);
}
protected override void OnNavigatedTo(NavigationEventArgs e)
{
navigationHelper.OnNavigatedTo(e);
}
#endregion NavigationHelper registration
}
public class ItemData
{
public string UniqueID { get; set; }
public string Title { get; set; }
public string Group { get; set; }
public string ImagePath { get; set; }
}
}
使用Melbourne_Getaway.Common;
使用墨尔本大学Getaway.Data;
使用Newtonsoft.Json;
使用制度;
使用System.Collections.Generic;
使用System.Collections.ObjectModel;
使用Windows.Storage;
使用Windows.UI.Popups;
使用Windows.UI.Xaml.Controls;
使用Windows.UI.Xaml.Navigation;
墨尔本之旅
{
公共密封部分类收藏夹页面:第页
{
公共ObservableCollection项{get;set;}
private observedictionary defaultViewModel=new observedictionary();
私人导航助手导航助手;
私有rootobjectjsonline;
私有存储文件收藏夹;
私有字典ItemData=新字典();
公众喜爱
{
loadJson();
getFavFile();
this.InitializeComponent();
this.navigationHelper=新的navigationHelper(this);
this.navigationHelper.LoadState+=navigationHelper\u LoadState;
}
私有void setupObservableCollection()
{
Items=新的ObservableCollection(ItemData.Values);
DataContext=项目;
}
私有异步void loadJson()
{
var file=wait-StorageFile.getfilefromApplicationUrisync(新Uri(“ms”)-appx:///DataModel/SampleData.json"));
字符串行=等待文件IO.ReadTextAsync(文件);
jsonLines=JsonConvert.DeserializeObject(行);
饲料项目();
}
私有异步void getFavFile()
{
Windows.Storage.StorageFolder StorageFolder=Windows.Storage.ApplicationData.Current.LocalFolder;
filefavorities=wait-storageFolder.GetFileAsync(“MelbGetaway.fav”);
}
专用异步void feedItems()
{
如果(等待文件IO.ReadTextAsync(文件收藏夹)!=“”)
{
foreach(wait FileIO.ReadLinesAsync(filefavorites)中的var行)
{
foreach(jsonLines.Groups中的var组)
{
foreach(Group.Items中的变量项)
{
如果(Item.UniqueId==行)
{
var storage=newitemdata()
{
标题=项目。标题,
UniqueID=Item.UniqueID,
ImagePath=Item.ImagePath,
组=组。标题
};
ItemData.Add(storage.UniqueID,storage);
}
}
}
}
}
其他的
{//仅当收藏夹文件为空时才应执行,是否首次使用?
foreach(jsonLines.Groups中的var组)
{
foreach(Group.Items中的变量项)
{
var storage=newitemdata()
{
标题=项目。标题,
UniqueID=Item.UniqueID,
ImagePath=Item.ImagePath,
组=组。标题
};
ItemData.Add(storage.UniqueID,storage);
等待FileIO.AppendTextAsync(FileFavorites,Item.UniqueId+“\r\n”);
}
}
}
setupobserveCollection();
}
公共可观测默认视图模型
{
获取{返回this.defaultViewModel;}
}
#区域导航辅助加载程序
公共导航帮助器导航帮助器
{
获取{返回this.navigationHelper;}
}
专用异步void消息框(字符串消息)
{
MessageDialog=新建MessageDialog(消息);
wait dialog.ShowAsync();
}
私有异步void navigationHelper\u LoadState(对象发送方,LoadStateEventArgs e)
{
var sampleDataGroups=await SampleDataSource.GetGroupsAsync();
this.defaultViewModel[“Groups”]=sampleDataGroups;
}
#endregion NavigationHelper加载程序
#区域导航助手注册
受保护的覆盖无效OnNavigatedFrom(NavigationEventArgs e)
{
navigationHelper.OnNavigatedFrom(e);
}
受保护的