一旦List属性值更改，我想更新绑定值：
MyContentView.xmal
Spacing="1">
<ffimageloading:CachedImage
FadeAnimationEnabled="true"
Source="{Binding ImageProduit}"
HeightRequest="{Binding ThumbnailHeight}"
Aspect="AspectFill"/>
<Label x:Name="lbldisp" Text="{Binding ArticleQt}" VerticalOptions="Center" HorizontalOptions="Center"></Label>
<Stepper Minimum="0" Maximum="10" Increment="1" HorizontalOptions="FillAndExpand" VerticalOptions="CenterAndExpand" ValueChanged="OnValueChanged" />
MyContentPage.xmal 对象将在此处加载
<ContentPage
xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="Fit_Plans.ProductsView"
xmlns:artina="clr-namespace:UXDivers.Artina.Shared;assembly=UXDivers.Artina.Shared"
xmlns:fitPlans="clr-namespace:Fit_Plans;assembly=Fit_Plans"
Title="wwe">
<StackLayout Grid.Row="0">
<Label Text="{fitPlans:TranslateExtension Text=nbrJour}"
FontAttributes="Bold"
HorizontalOptions="Center" />
<Label Text="{Binding Source={x:Reference NbrJour},
Path=Value ,
StringFormat={fitPlans:TranslateExtension Text=dragnbrJour}}"
x:Name="LabelNbrJour"
FontSize="Small"
HorizontalOptions="Center"
VerticalOptions="CenterAndExpand" />
<Slider x:Name="NbrJour"
Maximum="7"
Minimum="1"
ValueChanged="NbrJour_OnValueChanged"
VerticalOptions="CenterAndExpand" />
</StackLayout>
<StackLayout VerticalOptions="FillAndExpand"
HorizontalOptions="FillAndExpand"
x:Name="ProduitsLayout">
<!--Here products will be displayed --->
</StackLayout>
/ContentPage>
现在在 MyContentPage.xaml
中namespace Fit_Plans
{
public partial class ProductsView : ContentPage , INotifyPropertyChanged
{
private TapGestureRecognizer tapGestureRecognizer = new TapGestureRecognizer();
private HttpClient _Client = new HttpClient();
private List<PlanModel> listproduits = new List<PlanModel>();
private string api;
private string siteUrl;
private PlanModel planModel;
private List<Product> listProduits;
public string titreProduit { get; set; }
private ArticleViewModel articleView;
private List<PlanDefinition> listArticles;
private List<PlanDefinition> listArticlesFinal;
private ObservableCollection<PlanDefinition> timeStepDataCollection;
private Stepper stepper;
public event EventHandler<ValueChangedEventArgs> ValueChanged;
private List<Label> lbLabel;
public event PropertyChangedEventHandler PropertyChanged;
private PlanOrderTemplate item;
public ProductsView()
{
planModel = new PlanModel();
articleView = new ArticleViewModel();
lbLabel = new List<Label>();
stepper =new Stepper();
InitializeComponent ();
}
public ObservableCollection<PlanDefinition> TimeStepDataCollection
{
get
{
if (timeStepDataCollection == null)
{
timeStepDataCollection = new ObservableCollection<PlanDefinition>();
}
return timeStepDataCollection;
}
set
{
timeStepDataCollection = value;
}
}
public void HandlelbTexChanged(object sender, EventArgs e)
{
//Do something here
}
async protected override void OnAppearing()
{
listArticles= articleView.getArticlesFromPlan();
var evan = CultureInfo.CurrentCulture;
timeStepDataCollection = new ObservableCollection<PlanDefinition>(listArticles);
PopulateProductsLists(timeStepDataCollection);
PopulateOrderLists(timeStepDataCollection);
base.OnAppearing();
}
protected override void OnDisappearing()
{
listproduits = null;
base.OnDisappearing();
}
public void OnPropertyChanged([CallerMemberName] string name = "")
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
}
private void PopulateOrderLists(ObservableCollection<PlanDefinition> listArticles)
{
OrderTemplate prod = new OrderTemplate();
;
for (var i = 0; i < listArticles.Count; i++)
{
prod = new OrderTemplate();
prod.BindingContext = listArticles[i].Quantity;
OrderInformation.Children.Add(prod);
for (int j = 0; j < listArticles[i].ArticlesAvailable.Count; j++)
{
prod = new OrderTemplate();
prod.BindingContext = listArticles[i].ArticlesAvailable[j].ArticleQt;
OrderInformation.Children.Add(prod);
}
}
}
//TODO - adapter la product lsit pour faire afficher les items du menu
private void PopulateProductsLists(ObservableCollection<PlanDefinition> listArticles)
{
int labelIndex = 0;
int count = 0;
for (var i = 0; i < listArticles.Count; i++)
{
item = new PlanOrderTemplate();
long quanityArticles = listArticles[i].Quantity;
var lastHeight = "100";
var y = 0;
int column = 1;
var productTapGestureRecognizer = new TapGestureRecognizer();
ProduitsLayout.Children.Add((new Label
{
Text = listArticles[i].Name,
Style = Device.Styles.TitleStyle,
FontAttributes = FontAttributes.Bold,
TextColor = Color.Black
}));
for (int j = 0; j < listArticles[i].ArticlesAvailable.Count; j++)
{
productTapGestureRecognizer.Tapped += OnProductTapped;
MyGrid = new Grid();
listArticles[i].ArticlesAvailable[j].ImageProduit =
"https://fit-plans.com/" + listArticles[i].ArticlesAvailable[j].UrlSmallImage;
listArticles[i].ArticlesAvailable[j].Description =
Html.FromHtml(listArticles[i].ArticlesAvailable[j].Description).ToString();
item = new PlanOrderTemplate();
if (j % 2 == 0)
{
column = 0;
y++;
}
else
{
column = 1;
}
listArticles[i].ArticlesAvailable[j].ThumbnailHeight = lastHeight;
item.BindingContext = listArticles[i].ArticlesAvailable[j];
item.GestureRecognizers.Add(productTapGestureRecognizer);
item.lbldispChanged += item.OnHashtagLife;
ProduitsLayout.Children.Add(item);
}
}
}
void OnValueChanged(object sender, ValueChangedEventArgs e)
{
/* lbldisp.Text = e.NewValue.ToString();
//Fire the event - notifying all subscribers
if (lbldispChanged != null)
lbldispChanged(this, null);*/
}
private async void OnProductTapped(Object sender, EventArgs e)
{
var selectedItem = (ArticlesAvailable)((PlanOrderTemplate)sender).BindingContext;
DisplayAlert("Info", selectedItem.Description, "OK");
}
private void NbrJour_OnValueChanged(object sender, ValueChangedEventArgs e)
{
LabelNbrJour.Text = Math.Round(e.NewValue).ToString();
for (var i = 0; i < timeStepDataCollection.Count; i++)
{
timeStepDataCollection[i].MaximumQuantity = timeStepDataCollection[i].Quantity * (long)Math.Round(e.NewValue);
for (var j = 0; j < timeStepDataCollection[i].ArticlesAvailable.Count; j++)
{
timeStepDataCollection[i].ArticlesAvailable[j].ArticleQt = 5;
}
}
}
}
}
无论何时item.lbldispChanged += item.OnHashtagLife;
触发此方法没有任何问题：
private void NbrJour_OnValueChanged(object sender, ValueChangedEventArgs e)
{
LabelNbrJour.Text = Math.Round(e.NewValue).ToString();
for (var i = 0; i < timeStepDataCollection.Count; i++)
{
timeStepDataCollection[i].MaximumQuantity = timeStepDataCollection[i].Quantity * (long)Math.Round(e.NewValue);
for (var j = 0; j < timeStepDataCollection[i].ArticlesAvailable.Count; j++)
{
timeStepDataCollection[i].ArticlesAvailable[j].ArticleQt = 5;
}
}
但是timeStepDataCollection[i].ArticlesAvailable[j].ArticleQt = 5;并没有在对应标签中得到更新
<Label x:Name="lbldisp" Text="{Binding ArticleQt}" VerticalOptions="Center" HorizontalOptions="Center"></Label>
如何在滑块NbrJour发布值更改时使timeStepDataCollection动态通知View并更新值？