Question

我需要知道为什么在我的页面中出现三次相同的项目，只显示一次。

最近点中显示的项Achat de Voiture也应出现在固定和需要注意;事实并非如此。相反，我们有一个显示空项目的空白区域。

在我看来，这是因为同一个视图模型被重复用于三个视图但是这是一个问题吗？

更新

关于代码 - 视图模型代码可能太长而无法发布，而XAML代码部分来自自定义Listview（来自其他程序集）

可以提供帮助的信息 - 应用程序一直运行良好。这个问题最近开始，我相信我最近做的其中一个行动可能是一个原因：

我更改了Firebase库
我将本地数据库库从Lex.db更改为LiteDB
我更新了我的Xamarin.Forms包
昨天我更新了Win10

我希望这会有所帮助

更新2 （代码）

ItemTemplate

的XAML代码

<ListView.ItemTemplate>
    <DataTemplate>
        <ViewCell>
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*" />
                    <ColumnDefinition Width="auto" />
                    <ColumnDefinition Width="10" />
                </Grid.ColumnDefinitions>
                <StackLayout Grid.Column="0" Orientation="Horizontal">
                    <Label Text="{Binding Name}" 
                            VerticalOptions="Center" 
                            LineBreakMode="TailTruncation" />
                    <Label Text="{Binding ContactName}" 
                            VerticalOptions="Center" 
                            LineBreakMode="TailTruncation" 
                            TextColor="{StaticResource secondary_text}">
                        <Label.IsVisible>
                            <OnIdiom x:TypeArguments="x:Boolean" Desktop="True" Tablet="True" TV="True"  Phone="False" />
                        </Label.IsVisible>
                    </Label>
                    <baseView:FALabel Icon="FACalendarCheckO"
                                        IsVisible="{Binding HasDue}"
                                        TextColor="{StaticResource secondary_text}" 
                                        VerticalOptions="Center"  />
                    <Label Text="{Binding FormattedDueDateAgo}" 
                            IsVisible="{Binding HasDue}" FontAttributes="Italic"
                            LineBreakMode="HeadTruncation" 
                            HorizontalOptions="FillAndExpand"
                            TextColor="{StaticResource secondary_text}" 
                            VerticalOptions="Center" />
                    <baseView:FALabel Icon="{Binding EmotionIcon}" 
                                    TextColor="{Binding EmotionColor}" 
                                    BackgroundColor="Transparent" 
                                    IsVisible="{Binding HasEmotion}" 
                                    VerticalOptions="Center" HorizontalOptions="EndAndExpand" />
                </StackLayout>
                <Label Grid.Column="1" Text="{Binding DisplayAmountWithCurrency}" 
                        TextColor="{Binding DisplayAmountTextColor}" 
                        HorizontalOptions="End"
                        VerticalOptions="Center" 
                        LineBreakMode="NoWrap" />
                <BoxView Grid.Column="2" BackgroundColor="{Binding DueAmountTextColor}" HorizontalOptions="FillAndExpand" />
            </Grid>
        </ViewCell>
    </DataTemplate>
</ListView.ItemTemplate>

我设置BindingContext

//I made the mothod async to avoid the page to freeze the second time it is instantiated
protected async override void OnAppearing()
{
    base.OnAppearing();
    if(BindingContext == null)
    {
        HVM = new HomePageVM();
        BindingContext = HVM;
    }

    if (CurrentCount != Main.API.DebtsDB.Entries.Count)
    {
        CurrentCount = Main.API.DebtsDB.Entries.Count;
        var l = Main.API.DebtsDB.Entries.ToList();
        l.Sort((x, y) => (y.Modified.CompareTo(x.Modified) * 1024) + (x.IsFather.CompareTo(y.IsFather) * -1));
        var Pending = new HomeDataGroup(l.Where((d) => d.IsNormalDebt && !d.StatusIgnored && !d.IsFather && !d.StatusValidated && d.HasDue && Math.Abs((d.DueDate - Core.Main.Now).TotalDays) < 90))
        {
            Title = "Close (90 days)",
            Icon = FontIcon.FACalendar,
            ShortTitle = "C",
        };
        var Pinned = new HomeDataGroup(l.Where((d) => d.IsNormalDebt && (d.PinnedUp || d.PinnedUpPlus)))
        {
            Title = "Pinned",
            Icon = FontIcon.FAThumbTack,
            IconColor = (Color)Application.Current.Resources["pinned_color"],
            ShortTitle = "P",
        };
        var Attention = new HomeDataGroup(l.Where(d => d.IsNormalDebt && d.EmotionWarning))
        {
            Title = "Need Attention",
            Icon = Cash.GetEmotionIcon(BaseEmotion.Warning),
            IconColor = Cash.GetEmotionColor(BaseEmotion.Warning),
            ShortTitle = "A",
        };
        var NotValidated = new HomeDataGroup(l.Where(d => d.IsNormalDebt && !d.StatusIgnored && !d.IsFather && !d.HasDue && !d.StatusValidated))
        {
            Title = "Awaiting Confirmation",
            Icon = FontIcon.FACheck,
            IconColor = (Color)Application.Current.Resources["pinned_color"],
            ShortTitle = "C",
        };
        var Recents = new HomeDataGroup(l.Where((d) => d.IsNormalDebt && (Main.Now - d.ModifiedDate).Days < 14))
        {
            Title = "Recents (2 weeks ago)",
            Icon = FontIcon.FAClockO,
            ShortTitle = "R",
        };

        var ls = new List<HomeDataGroup>();
        if (Pinned.Count > 0)
            ls.Add(Pinned);
        if (Pending.Count > 0)
            ls.Add(Pending);
        if (Attention.Count > 0)
            ls.Add(Attention);
        if (NotValidated.Count > 0)
            ls.Add(NotValidated);
        if (Recents.Count > 0)
            ls.Add(Recents);

        await Task.Delay(200); // The page was freezing without this
        HVM.HomeItems = ls;
    }
}

DebtsDB是我用来获取模型并生成ViewModels

的类

DebtsDB = new Core.DB.RunningDB<Cash, CashVM>();
public class RunningDB<T, T_VM> : IRunningDB<T>
        where T : BaseHistory
        where T_VM : BaseHistory, new()
{
    public RunningDB()
    {
        Entries = new ObservableCollection<T_VM>();
        CacheEntries = new Dictionary<string, T_VM>();
    }
    public RealtimeDatabase<T> DB => IDB as RealtimeDatabase<T>;
    private IRealtimeDatabase IDB { get; set; }
    public ObservableCollection<T_VM> Entries { get; set; }
    public Dictionary<string, T_VM> CacheEntries { get; set; }

    IDisposable Subscription;
    public void Observe()
    {
        try
        {
            var a = (from tr in DB.AsObservable()
                     where !string.IsNullOrEmpty(tr.Key)
                     select new { tr }
                     );
            Subscription = a.Subscribe(onNext: pair => Observe(pair.tr.Key, pair.tr.Object, Entries, CacheEntries));
        }
        catch (Exception ex)
        {
            Main.AppStatus.OnError(new ErrorData { Ex = ex, FuncName = "Observe" });
        }

    }
    protected void Observe(string key, T o, Collection<T_VM> l, Dictionary<string, T_VM> cache)
    {
        try
        {
            Main.AppStatus.IsRefreshing = false;
            if (o == null || o.StatusDeleted)
                ObserveDeleted(key, l, cache);
            else
                ObserveUpdate(key, o, l, cache);
        }
        catch (Exception ex)
        {
            Main.AppStatus.OnError(new ErrorData { Ex = ex, FuncName = "Observe" });
        }
    }
    protected async void ObserveUpdate(string key, T o, Collection<T_VM> l, Dictionary<string, T_VM> cache)
    {
        o.Key = key;
        T_VM o_vm = BaseHistory.Create<T, T_VM>(o);
        o_vm.Load();
        if (!cache.ContainsKey(key))
        {
            cache[key] = o_vm;
            await CrossCollection.Current.AddAsync(l, o_vm);
        }
        else
        {
            cache[key] = o_vm;
            for (int j = 0; j < l.Count; j++)
            {
                if (l[j].Key == key)
                {
                    await CrossCollection.Current.ReplaceAsync(l, j, o_vm);
                    break;
                }
            }
        }
    }
    protected async void ObserveDeleted<B_VM>(string key, Collection<B_VM> l, Dictionary<string, B_VM> cache)
        where B_VM : BaseHistory
    {
        if (cache.ContainsKey(key))
        {
            await CrossCollection.Current.RemoveAsync(l, cache[key]);
            cache.Remove(key);
        }
    }

    public async Task Pull()
    {
        await IDB.PullAsync();
    }
}

ViewModel

public class CashVM : Cash, IBasePicture, IBaseHistoryVM, ISelectable
{
    public CashVM()
    {
        Main.AppStatus.PropertyChanged += Status_PropertyChanged;
    }
    public string DisplayDate => HasDue ? (char)FontIcon.FACalendarCheckO + " " + FormattedDueDate : FormattedStartDate;
    public string DisplayAmount => CashExt.FormatAmmoutWithSign(Amount, StatusIgnored, StatusValidated);
    public string DisplayBaseAmount => (BaseAmount != 0 && !this.DebtShouldSum() ?
        (BaseAmount > 0 ? "+" : "-")
        : "") + FormattedBaseAmount;
    public string DisplayAmountWithCurrency => Core.Main.Setting.UserSetting.Currency.AmountWithCurrency(DisplayAmount);
    public string DisplayBaseAmountWithCurrency => Core.Main.Setting.UserSetting.Currency.AmountWithCurrency(DisplayBaseAmount);

    public Color DisplayAmountTextColor => StatusIgnored || !StatusValidated ?
        (Color)Main.App.Resources["secondary_text"]
        : AmountTextColor;
    public Color DisplayBaseAmountTextColor => !this.DebtShouldSum() ?
        (Color)Main.App.Resources["secondary_text"]
        : BaseAmountTextColor;
    public bool NeedValidation => !IsFather && !StatusIgnored && !StatusValidated;
    public bool ContactVisible => !HasParentContact && !string.IsNullOrEmpty(ContactName);
    public bool SubjectVisible => !HasParentSubject && !string.IsNullOrEmpty(Name);
    public override void Load()
    {
        base.Load();
    }
}

UWP - 查看模型和多个视图问题

0 个答案: