Xamarin 表单 - 未检测到更改答案

【问题标题】：Xamarin Forms - Changes aren't detectedXamarin 表单 - 未检测到更改
【发布时间】：2020-10-30 13:19:19
【问题描述】：

我一直在尝试创建一个自定义搜索字段，该字段应在键入时即时将对象添加到列表中。但由于某种原因，它只在我热重载时显示带有项目的列表。

CreateHerdPageViewModel

   public class CreateHerdPageViewModel : ViewModelBase
    {
        private IHerdService herdService;
        private string searchInput;
        public string SearchInput { get => searchInput; 
            set { 
                SetProperty(ref searchInput, value);
                RaisePropertyChanged(nameof(HerdSearchResults));
            } 
        }

        private List<Herd> herdSearchResults;
        public List<Herd> HerdSearchResults
        {
            get => herdSearchResults;

            set {
                SetProperty(ref herdSearchResults, value);
                }
        }

        private List<Herd> allHerds;
        public List<Herd> AllHerds { get => allHerds; set => SetProperty(ref allHerds, value); }

        public DelegateCommand SearchChrOrAddressCommand { get; set; }
        public CreateHerdPageViewModel(INavigationService navigationService, IHerdService herdService)
            : base(navigationService)
        {
            this.herdService = herdService;
            SearchChrOrAddressCommand = new DelegateCommand(SearchChrOrAddress);
        }
        private void SearchChrOrAddress()
        {
            Herd herdMatch = new Herd();
            for (int i = 0; i < AllHerds.Count; i++)
            {
                herdMatch = AllHerds[i];
            }
            if (herdMatch.ChrAddress.Area.Contains(SearchInput))
            {
                if (HerdSearchResults.Contains(herdMatch) == false)
                {
                    HerdSearchResults.Add(herdMatch);
                    RaisePropertyChanged(nameof(HerdSearchResults));
                } 
            }
            
        }
        public async override void OnNavigatedTo(INavigationParameters parameters)
        {
            base.OnNavigatedTo(parameters);
            AllHerds = await herdService.GetHerds();
            HerdSearchResults = new List<Herd>();
        }


    }
}

CreateHerdPage.Xaml

xmlns:yummy="clr-namespace:Xamarin.Forms.PancakeView;assembly=Xamarin.Forms.PancakeView"
xmlns:b="clr-namespace:Prism.Behaviors;assembly=Prism.Forms"
xmlns:CustomRenderer="clr-namespace:ChrApp.CustomRenderer">

                   <yummy:PancakeView
                        Grid.Column="0"
                        Grid.Row="0"
                        Grid.ColumnSpan="3"
                        CornerRadius="10">
                    <CustomRenderer:NoUnderlineEntry
                            x:Name="SearchField"
                            Style="{StaticResource UpdateEntry}"
                            Margin="0"
                            TextChanged="RemovceSearchIcon"
                            Text="{Binding SearchInput}">
                        <CustomRenderer:NoUnderlineEntry.Behaviors>
                            <b:EventToCommandBehavior
                                EventName="TextChanged"
                                Command="{Binding SearchChrOrAddressCommand}"/>
                        </CustomRenderer:NoUnderlineEntry.Behaviors>
                    </CustomRenderer:NoUnderlineEntry>
                </yummy:PancakeView>

如您所见，我尝试了不同的方法让它识别更改，但没有运气。

有人可以告诉我我缺少什么吗？

提前致谢

【问题讨论】：

使用 ObservableCollection，而不是 List
你解决了这个问题吗？请更新。

标签： c# xaml xamarin xamarin.forms mvvm

【解决方案1】：

所以问题是我使用了普通的List，而不是ObservableCollection。所以切换到这个解决了这个问题。

【讨论】：