UWP При переходе с TemplateSelector на пользовательский элемент управления привязка больше не отображается - PullRequest
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UWP При переходе с TemplateSelector на пользовательский элемент управления привязка больше не отображается

0 голосов
/ 05 мая 2020

Следуя рабочему решению, предоставленному Ричардом Чжаном - MSFT в моем вопросе UWP Treeview с селектором данных, генерирующим ошибку в App.g.cs, когда я изменяю размер окна Я попытался преобразовать вторую группу данных шаблоны в элемент управления, чтобы иметь более понятный код и попытаться решить некоторые другие проблемы визуализации. Код компилируется, но ничего не показывает.

Рабочий код с помощью TreeView Template Selector: 

    <Page.Resources>
        <DataTemplate
            x:Key="ItemTemplate"
            x:DataType="model:MTreeViewBase"
            x:DefaultBindMode="OneWay">
            <winui:TreeViewItem IsExpanded="False" ItemsSource="{x:Bind Visits}">
                <controls1:TreeViewControl Data="{x:Bind}" />
            </winui:TreeViewItem>
        </DataTemplate>

        <DataTemplate
            x:Key="PAZContentTemplate"
            x:DataType="model:MTreeViewPaz"
            x:DefaultBindMode="OneWay">
            <StackPanel>
                <TextBlock Style="{StaticResource TitleTextBlockStyle}" Text="{x:Bind Name}" />
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                    </Grid.RowDefinitions>
                    <TextBlock
                        Grid.Row="0"
                        Grid.Column="0"
                        Margin="{StaticResource MediumTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Cognome" />
                    <TextBlock
                        Grid.Row="1"
                        Grid.Column="0"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Cognome}" />
                    <TextBlock
                        Grid.Row="0"
                        Grid.Column="1"
                        Margin="{StaticResource MediumTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Nome" />
                    <TextBlock
                        Grid.Row="1"
                        Grid.Column="1"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Nome}" />
                </Grid>
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                    </Grid.RowDefinitions>
                    <TextBlock
                        Grid.Row="0"
                        Grid.Column="0"
                        Margin="{StaticResource MediumTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Telefono 1" />
                    <TextBlock
                        Grid.Row="1"
                        Grid.Column="0"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Telef1}" />
                    <TextBlock
                        Grid.Row="0"
                        Grid.Column="1"
                        Margin="{StaticResource MediumTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Telefono 2" />
                    <TextBlock
                        Grid.Row="1"
                        Grid.Column="1"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Telef2}" />
                    <TextBlock
                        Grid.Row="2"
                        Grid.Column="0"
                        Margin="{StaticResource XSmallTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Fax" />
                    <TextBlock
                        Grid.Row="3"
                        Grid.Column="0"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Fax}" />
                </Grid>
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                    </Grid.RowDefinitions>

                    <TextBlock
                        Grid.Row="0"
                        Grid.Column="0"
                        Grid.ColumnSpan="5"
                        Margin="{StaticResource MediumTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Indirizzo" />
                    <TextBlock
                        Grid.Row="1"
                        Grid.Column="0"
                        Grid.ColumnSpan="5"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Indir}" />

                    <TextBlock
                        Grid.Row="2"
                        Grid.Column="0"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Cap}" />
                    <TextBlock
                        Grid.Row="2"
                        Grid.Column="1"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Citta}" />
                    <TextBlock
                        Grid.Row="2"
                        Grid.Column="2"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text=" (" />
                    <TextBlock
                        Grid.Row="2"
                        Grid.Column="3"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Cap}" />
                    <TextBlock
                        Grid.Row="2"
                        Grid.Column="4"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text=")" />
                    <TextBlock
                        Grid.Row="3"
                        Grid.Column="0"
                        Grid.ColumnSpan="5"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Nazione}" />

                </Grid>
                <TextBlock
                    Margin="{StaticResource MediumTopMargin}"
                    Style="{StaticResource DetailSubTitleStyle}"
                    Text="Codice Fiscale" />
                <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Paz.CodFis}" />

                <TextBlock
                    Margin="{StaticResource MediumTopMargin}"
                    Style="{StaticResource DetailSubTitleStyle}"
                    Text="Nato il " />
                <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind BornDate}" />
                <TextBlock
                    Margin="{StaticResource XSmallTopMargin}"
                    Style="{StaticResource DetailSubTitleStyle}"
                    Text="in" />
                <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Paz.Naton}" />
                <StackPanel Orientation="Horizontal">
                    <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Paz.Natoa}" />
                    <TextBlock Text=" (" />
                    <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Paz.Natop}" />
                    <TextBlock Text=")" />
                </StackPanel>

                <TextBlock
                    Margin="{StaticResource MediumTopMargin}"
                    Style="{StaticResource DetailSubTitleStyle}"
                    Text="Clinica" />
                <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Paz.Clinica}" />

                <TextBlock
                    Margin="{StaticResource MediumTopMargin}"
                    Style="{StaticResource DetailSubTitleStyle}"
                    Text="Presentato da" />
                <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Paz.PresDa}" />

                <TextBlock
                    Margin="{StaticResource MediumTopMargin}"
                    Style="{StaticResource DetailSubTitleStyle}"
                    Text="Assicurazione" />
                <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Paz.Assicurazione}" />
            </StackPanel>
        </DataTemplate>
        <DataTemplate
            x:Key="APPContentTemplate"
            x:DataType="model:MTreeViewVisit"
            x:DefaultBindMode="OneWay">
            <StackPanel>
                <TextBlock
                    Foreground="{x:Bind ImageColor}"
                    Style="{StaticResource TitleTextBlockStyle}"
                    Text="Analisi Patologia Prossima" />
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                    </Grid.RowDefinitions>
                    <TextBlock
                        Grid.Row="0"
                        Grid.Column="0"
                        Margin="{StaticResource MediumTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Clinica" />
                    <TextBlock
                        Grid.Row="1"
                        Grid.Column="0"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Visit.(model:TApp.Clinica)}" />
                    <TextBlock
                        Grid.Row="0"
                        Grid.Column="1"
                        Margin="{StaticResource MediumLeftTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Data" />
                    <TextBlock
                        Grid.Row="1"
                        Grid.Column="1"
                        Margin="{StaticResource MediumLeftMargin}"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Visit.(model:TApp.DataS)}" />
                </Grid>

                <TextBlock
                    Margin="{StaticResource MediumTopMargin}"
                    Style="{StaticResource DetailSubTitleStyle}"
                    Text="Descrizione" />
                <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Visit.(model:TApp.Descr)}" />
            </StackPanel>
        </DataTemplate>
    </Page.Resources>

        <templateSelectors:TreeViewDataContentTemplateSelector
            x:Key="TreeViewDataContentTemplateSelector"
            APPTemplate="{StaticResource APPContentTemplate}"
            PAZTemplate="{StaticResource PAZContentTemplate}" />

        <ScrollViewer Grid.Column="1" Padding="{StaticResource DetailPageMargin}" x:DefaultBindMode="OneWay">
            <ContentControl Content="{x:Bind SelectedItem}" ContentTemplateSelector="{StaticResource TreeViewDataContentTemplateSelector}" />
        </ScrollViewer>

Когда я щелкаю элемент в TreeView, на панели отображается правильная информация.

НО, если я попробую это:

TrewView.xaml 

       <ScrollViewer Grid.Column="1" Padding="{StaticResource DetailPageMargin}" >
            <controls1:TreeViewContentControl Data="{x:Bind (model:MTreeViewBase)SelectedItem, Mode=OneWay}"    />
        </ScrollViewer>

TreeViewContentControl.xaml 

<UserControl
    x:Class="TitoDoc2020.Views.TreeViewContentControl"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:TitoDoc2020.Views"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:model="using:TitoDoc2020.Models"
    mc:Ignorable="d"
    d:DesignHeight="300"
    d:DesignWidth="400">

    <UserControl.Resources>
        <DataTemplate
            x:Name="PAZContentTemplate"
            x:DataType="model:MTreeViewPaz"
            x:DefaultBindMode="OneWay">
            <StackPanel>
                <TextBlock Style="{StaticResource TitleTextBlockStyle}" Text="{x:Bind Name}" />
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                    </Grid.RowDefinitions>
                    <TextBlock
                        Grid.Row="0"
                        Grid.Column="0"
                        Margin="{StaticResource MediumTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Cognome" />
                    <TextBlock
                        Grid.Row="1"
                        Grid.Column="0"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Cognome}" />
                    <TextBlock
                        Grid.Row="0"
                        Grid.Column="1"
                        Margin="{StaticResource MediumTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Nome" />
                    <TextBlock
                        Grid.Row="1"
                        Grid.Column="1"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Nome}" />
                </Grid>
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                    </Grid.RowDefinitions>
                    <TextBlock
                        Grid.Row="0"
                        Grid.Column="0"
                        Margin="{StaticResource MediumTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Telefono 1" />
                    <TextBlock
                        Grid.Row="1"
                        Grid.Column="0"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Telef1}" />
                    <TextBlock
                        Grid.Row="0"
                        Grid.Column="1"
                        Margin="{StaticResource MediumTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Telefono 2" />
                    <TextBlock
                        Grid.Row="1"
                        Grid.Column="1"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Telef2}" />
                    <TextBlock
                        Grid.Row="2"
                        Grid.Column="0"
                        Margin="{StaticResource XSmallTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Fax" />
                    <TextBlock
                        Grid.Row="3"
                        Grid.Column="0"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Fax}" />
                </Grid>
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                    </Grid.RowDefinitions>

                    <TextBlock
                        Grid.Row="0"
                        Grid.Column="0"
                        Grid.ColumnSpan="5"
                        Margin="{StaticResource MediumTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Indirizzo" />
                    <TextBlock
                        Grid.Row="1"
                        Grid.Column="0"
                        Grid.ColumnSpan="5"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Indir}" />

                    <TextBlock
                        Grid.Row="2"
                        Grid.Column="0"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Cap}" />
                    <TextBlock
                        Grid.Row="2"
                        Grid.Column="1"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Citta}" />
                    <TextBlock
                        Grid.Row="2"
                        Grid.Column="2"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text=" (" />
                    <TextBlock
                        Grid.Row="2"
                        Grid.Column="3"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Cap}" />
                    <TextBlock
                        Grid.Row="2"
                        Grid.Column="4"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text=")" />
                    <TextBlock
                        Grid.Row="3"
                        Grid.Column="0"
                        Grid.ColumnSpan="5"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Paz.Nazione}" />

                </Grid>
                <TextBlock
                    Margin="{StaticResource MediumTopMargin}"
                    Style="{StaticResource DetailSubTitleStyle}"
                    Text="Codice Fiscale" />
                <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Paz.CodFis}" />

                <TextBlock
                    Margin="{StaticResource MediumTopMargin}"
                    Style="{StaticResource DetailSubTitleStyle}"
                    Text="Nato il " />
                <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind BornDate}" />
                <TextBlock
                    Margin="{StaticResource XSmallTopMargin}"
                    Style="{StaticResource DetailSubTitleStyle}"
                    Text="in" />
                <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Paz.Naton}" />
                <StackPanel Orientation="Horizontal">
                    <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Paz.Natoa}" />
                    <TextBlock Text=" (" />
                    <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Paz.Natop}" />
                    <TextBlock Text=")" />
                </StackPanel>

                <TextBlock
                    Margin="{StaticResource MediumTopMargin}"
                    Style="{StaticResource DetailSubTitleStyle}"
                    Text="Clinica" />
                <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Paz.Clinica}" />

                <TextBlock
                    Margin="{StaticResource MediumTopMargin}"
                    Style="{StaticResource DetailSubTitleStyle}"
                    Text="Presentato da" />
                <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Paz.PresDa}" />

                <TextBlock
                    Margin="{StaticResource MediumTopMargin}"
                    Style="{StaticResource DetailSubTitleStyle}"
                    Text="Assicurazione" />
                <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Paz.Assicurazione}" />
            </StackPanel>
        </DataTemplate>

        <DataTemplate
            x:Name="APPContentTemplate"
            x:DataType="model:MTreeViewVisit"
            x:DefaultBindMode="OneWay">
            <StackPanel>
                <TextBlock
                    Foreground="{x:Bind ImageColor}"
                    Style="{StaticResource TitleTextBlockStyle}"
                    Text="Analisi Patologia Prossima" />
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="Auto" />
                    </Grid.RowDefinitions>
                    <TextBlock
                        Grid.Row="0"
                        Grid.Column="0"
                        Margin="{StaticResource MediumTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Clinica" />
                    <TextBlock
                        Grid.Row="1"
                        Grid.Column="0"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Visit.(model:TApp.Clinica)}" />
                    <TextBlock
                        Grid.Row="0"
                        Grid.Column="1"
                        Margin="{StaticResource MediumLeftTopMargin}"
                        Style="{StaticResource DetailSubTitleStyle}"
                        Text="Data" />
                    <TextBlock
                        Grid.Row="1"
                        Grid.Column="1"
                        Margin="{StaticResource MediumLeftMargin}"
                        Style="{StaticResource DetailBodyBaseMediumStyle}"
                        Text="{x:Bind Visit.(model:TApp.DataS)}" />
                </Grid>

                <TextBlock
                    Margin="{StaticResource MediumTopMargin}"
                    Style="{StaticResource DetailSubTitleStyle}"
                    Text="Descrizione" />
                <TextBlock Style="{StaticResource DetailBodyBaseMediumStyle}" Text="{x:Bind Visit.(model:TApp.Descr)}" />
            </StackPanel>
        </DataTemplate>
    </UserControl.Resources>

    <Grid>
        <ContentControl x:Name="MainContent" />
    </Grid>
</UserControl>

TreeViewContentControl.xaml.cs 

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using TitoDoc2020.Models;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

// The User Control item template is documented at https://go.microsoft.com/fwlink/?LinkId=234236

namespace TitoDoc2020.Views
{
    public sealed partial class TreeViewContentControl : UserControl
    {
#if LOG
        private static readonly NLog.Logger Logger = NLog.LogManager.GetCurrentClassLogger();
#endif
        public MTreeViewBase Data
        {
            get { return (MTreeViewBase)GetValue(DataProperty); }
            set { SetValue(DataProperty, value); }
        }

        // Using a DependencyProperty as the backing store for Data.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty DataProperty =
            DependencyProperty.Register("Data", typeof(MTreeViewBase), typeof(TreeViewContentControl), new PropertyMetadata(null, new PropertyChangedCallback(Data_Changed)));

        private static void Data_Changed(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if (e.NewValue != null)
            {
                var instance = d as TreeViewContentControl;
                if (e.NewValue is MTreeViewPaz)
                {
                    instance.MainContent.ContentTemplate = instance.PAZContentTemplate;
                }
                else
                {
                    //instance.MainContent.ContentTemplate = instance.VisitTemplate;
                    switch (((MTreeViewVisit)e.NewValue).Type)
                    {
                        // Generic Visits
                        case "APP":
                            instance.MainContent.ContentTemplate = instance.APPContentTemplate;
                            break;
                        default:
                            if (e.NewValue != null)
                            {
#if LOG
                                Logger.Error("Should never be default");
#endif
                            }
                            break;
                    }
                }

            }
        }
        public TreeViewContentControl()
        {
            this.InitializeComponent();
        }
    }
}

Он не показывает никакого содержимого в x: Bind. Страница изменена правильно, отображается stati c текст, но не реальные данные.

Я думаю, что сделал то же самое, что и другой элемент управления, но не могу понять, что я напутал

1 Ответ

0 голосов
/ 06 мая 2020

Благодаря Peter Spada и его удивительной помощи мне удалось заставить его работать:

вот проблема: я устанавливаю instance.MainContent.ContentTemplate на DataTemplate с x:DataType=”model:MTreeViewPaz”. Однако для instance.MainContent никогда не устанавливаются значения Content или DataContext, поэтому используется значение DataContext по умолчанию. Значение по умолчанию DataContext наследуется от дерева XAML и происходит от root ShellPage:

Вот почему InvalidCastException не удалось преобразовать ShellPage в MTreeViewPaz.

Мне удалось исправить это, вручную установив DataContext, как показано ниже.

TreeViewContentControl.xaml.cs 

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using TitoDoc2020.Models;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

// The User Control item template is documented at https://go.microsoft.com/fwlink/?LinkId=234236

namespace TitoDoc2020.Views
{
    public sealed partial class TreeViewContentControl : UserControl
    {
#if LOG
        private static readonly NLog.Logger Logger = NLog.LogManager.GetCurrentClassLogger();
#endif
        public MTreeViewBase Data
        {
            get { return (MTreeViewBase)GetValue(DataProperty); }
            set { SetValue(DataProperty, value); }
        }

        // Using a DependencyProperty as the backing store for Data.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty DataProperty =
            DependencyProperty.Register("Data", typeof(MTreeViewBase), typeof(TreeViewContentControl), new PropertyMetadata(null, new PropertyChangedCallback(Data_Changed)));

        private static void Data_Changed(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if (e.NewValue != null)
            {
                var instance = d as TreeViewContentControl;
                if (e.NewValue is MTreeViewPaz)
                {
                    instance.MainContent.ContentTemplate = instance.PAZContentTemplate;
                }
                else
                {
                    //instance.MainContent.ContentTemplate = instance.VisitTemplate;
                    switch (((MTreeViewVisit)e.NewValue).Type)
                    {
                        // Generic Visits
                        case "APP":
                            instance.MainContent.ContentTemplate = instance.APPContentTemplate;
                            break;
                        default:
                            if (e.NewValue != null)
                            {
#if LOG
                                Logger.Error("Should never be default");
#endif
                            }
                            break;
                    }
                }

                instance.MainContent.DataContext = e.NewValue;

            }
        }
        public TreeViewContentControl()
        {
            this.InitializeComponent();
        }
    }
}
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