UWP开发---嵌套DataTemplate&模板选择器

时间 2019-11-07

标签 uwp 开发嵌套 datatemplate 模板选择器繁體版

原文原文链接

对于Json结构体items不彻底一致的状况下，在UWP平台是如何处理数据，并经过不一样的模板选择，进行显示呢？json

【嵌套Json分析】

[结构]

　　经过抓取index的API（点击请求API）获取到的json，来看主页的数据是嵌套结构的Json，而且在Recs结构体中的items具备不彻底一致性，结构以下图：api

如上图所示，recs有若干子项，可是展开子项的items便可发现app

还有其余就不依依列举图片出来了。ide

为了让开发工做更加简便，咱们能够新建两个类：Hanju,CommonVideo，设置好各种别的各个字段
spa

【DataTemplate嵌套】

[最低层次]

（韩剧，直播，视频等最外层的数据）3d

韩剧模板（图中那些转换器，宽度没必要在乎，后续文章会展开来说）code

 1 <DataTemplate x:Key="seriesTemplate">
 2             <Border Margin="2" Width="{Binding ElementName=hanjuThumb_width, Path=Width}">
 3                 <Grid>
 4                     <Grid.RowDefinitions>
 5                         <RowDefinition/>
 6                         <RowDefinition Height="20"/>
 7                     </Grid.RowDefinitions>
 8                     <RelativePanel CornerRadius="10">
 9                         <Image x:Name="thumb" Source="{Binding thumb}" HorizontalAlignment="Center"  Stretch="UniformToFill"/>
10                         <Image Source="/Assets/Icons/series_preview_icon.png" Visibility="{Binding isPreview,Converter={StaticResource BoolToVisibilityConverter}}" Height="40" RelativePanel.AlignRightWithPanel="True"/>
11                         <Image Source="/Assets/Icons/new_series.png" Visibility="{Binding updateTime,Converter={StaticResource IsNewUpdateConverter}}" Height="40" RelativePanel.AlignRightWithPanel="True"/>
12                         <Image Source="/Assets/Icons/live_ing.png" Visibility="{Binding living,Converter={StaticResource SeriesLivingImgShowConverter}}" RelativePanel.AlignRightWithPanel="True" Height="30"/>
13                         <TextBlock Text="{Binding count}" Foreground="White" RelativePanel.AlignBottomWithPanel="True" RelativePanel.AlignLeftWithPanel="True"/>
14                     <TextBlock  Text="{Binding rank}" Foreground="White" RelativePanel.AlignBottomWithPanel="True" RelativePanel.AlignRightWithPanel="True"/>
15                 </RelativePanel>
16                 <TextBlock Grid.Row="2" Text="{Binding name}" HorizontalAlignment="Center" TextWrapping="Wrap" Foreground="Black" FontSize="15"/>
17                 </Grid>
18             </Border>
19             </DataTemplate>

韩剧模板

视频模板orm

<DataTemplate x:Key="videoTemplate">
            <Border Margin="2" Width="{Binding ElementName=videoThumb_width,Path=Width}">
                <Grid>
                    <Grid.RowDefinitions>
                        <RowDefinition/>
                        <RowDefinition Height="40"/>
                    </Grid.RowDefinitions>
                    <Image Source="{Binding thumb}" Stretch="UniformToFill"/>
                    <TextBlock Grid.Row="2" Text="{Binding title}" TextTrimming="WordEllipsis" Foreground="Black"  FontSize="15" TextWrapping="Wrap"/>
                </Grid>
            </Border>
</DataTemplate>

视频模板

直播模板视频

 <DataTemplate x:Key="liveTemplate">
            <RelativePanel Width="{Binding ElementName=videoThumb_width,Path=Width}">
                <Image Source="{Binding thumb}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"/>
                <Image Source="/Assets/Icons/star_living.png" Width="50" Margin="5" RelativePanel.AlignRightWithPanel="True"/>
                <TextBlock Text="{Binding longTitle}" Foreground="White" RelativePanel.AlignLeftWithPanel="True" RelativePanel.AlignBottomWithPanel="True"/>
                <TextBlock Text="{Binding online}" Foreground="White" RelativePanel.AlignRightWithPanel="True" RelativePanel.AlignBottomWithPanel="True"/>
            </RelativePanel>
            </DataTemplate>

直播模板

[第二层次]

（是高一层次的模板，上述模板是下列这些的子项，整个韩剧集合，整个视频分类集合，GridView从左往右放单个视频）xml

<!--模板1韩剧-->
            <DataTemplate x:Key="DataTemplate1">
            <GridView IsItemClickEnabled="True" ItemClick="Hanju_ItemClick" Header="{Binding title,Converter={StaticResource StringFormatConverter},ConverterParameter='💕{0}>>'}" ItemsSource="{Binding items}" ItemTemplate="{StaticResource seriesTemplate}"/>
            </DataTemplate>
            <!--模板2明星视频-->
            <DataTemplate x:Key="DataTemplate2">
            <GridView IsItemClickEnabled="True" ItemClick="Video_ItemClick"  Header="{Binding title,Converter={StaticResource StringFormatConverter},ConverterParameter='💕{0}>>'}" ItemsSource="{Binding items}" ItemTemplate="{StaticResource videoTemplate}"/>
            </DataTemplate>
            <!--模板3其余视频-->
            <DataTemplate x:Key="DataTemplate3">
            <GridView  Header="{Binding title,Converter={StaticResource StringFormatConverter},ConverterParameter='💕{0}>>'}" ItemsSource="{Binding items}" ItemTemplate="{StaticResource videoTemplate}"/>
            </DataTemplate>
            <!--模板4直播-->
            <DataTemplate x:Key="DataTemplate4">
            <GridView  Visibility="{Binding extItems,Converter={StaticResource VisibilityConverter}}" Header="{Binding title,Converter={StaticResource StringFormatConverter},ConverterParameter='💕{0}>>'}" ItemsSource="{Binding extItems}" ItemTemplate="{StaticResource liveTemplate}"/>
            </DataTemplate>
            <!--模板5热门视频-->
            <DataTemplate x:Key="DataTemplate5">
            <GridView Header="{Binding title,Converter={StaticResource StringFormatConverter},ConverterParameter='💕{0}>>'}" ItemsSource="{Binding items}" ItemTemplate="{StaticResource videoTemplate}"/>
            </DataTemplate>

模板合集

[最高层次]

<ListView HorizontalAlignment="Center" SelectionMode="None" ItemsSource="recs" ItemTemplateSelector="{StaticResource Selector}" x:Name="lvRecs"/>

【模板选择器】

<Tools:MyTemplateSelector x:Key="Selector" x:Name="MyTemplateSelector" DataTemplate1="{StaticResource DataTemplate1}" DataTemplate2="{StaticResource DataTemplate2}" DataTemplate3="{StaticResource DataTemplate3}" DataTemplate4="{StaticResource DataTemplate4}" DataTemplate5="{StaticResource DataTemplate5}"/>

引入模板选择器

注意：在前台要引入自定义模板选择器的命名空间

xmlns:Tools="using:韩剧TV.Tools"

而后在listview里面加入ItemTemplateSelector="{StaticResource Selector}"

（见：2.3）

在json分析中能够看到，每个视频分类都有一个type字段，应该也是安卓控制模板选择的标志。咱们能够根据这个type来选择不一样的模板进行适配items项，那么Selector的后台代码以下：

namespace 韩剧TV.Tools
{
    class MyTemplateSelector:DataTemplateSelector
    {
        public DataTemplate DataTemplate1 { get; set; }
        public DataTemplate DataTemplate2 { get; set; }
        public DataTemplate DataTemplate3 { get; set; }
        public DataTemplate DataTemplate4 { get; set; }
        public DataTemplate DataTemplate5 { get; set; }
        protected override DataTemplate SelectTemplateCore(object item, DependencyObject container)
        {
            Recs rec = item as Recs;
            try
            {
                switch (rec.type)
                {
                    case 1:
                        return DataTemplate1;
                    case 2:
                        return DataTemplate2;
                    case 3:
                        return DataTemplate3;
                    case 4:
                        return DataTemplate4;
                    case 5:
                        return DataTemplate5;
                    default:
                        break;
                }
            }
            catch
            {
                return null;
            }
            return base.SelectTemplate(item, container);
        }
    }
}

能够看到自定义模板选择器继承于DataTemplateSelector，一样是WPF也存在的模板选择器

根据传入的item的type来返回对应的模板