WPF - 不为ListBox调用DataTemplateSelector [英] WPF - DataTemplateSelector is not called for ListBox

问题描述

这是我的XAML

<Window x:Class="WpfApp1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
        xmlns:sys="clr-namespace:System;assembly=mscorlib"
        xmlns:win="clr-namespace:System.Windows;assembly=PresentationCore"
        xmlns:local="clr-namespace:WpfApp1"
        mc:Ignorable="d" 
        >
 
    <Window.Resources>
        <DataTemplate x:Key="DefaultDataTemplate">
        </DataTemplate>
 
        <DataTemplate x:Key="SelectedNoteDataTemplate">
            <StackPanel Background="Orange">
                <TextBlock Text="Name:"  />
                <TextBlock Text="{Binding Name}"   />
            </StackPanel>
        </DataTemplate>
        
        <DataTemplate x:Key="NetworkDataTemplate">
            <StackPanel>
                <TextBlock Text="Name:"  />
                <TextBlock Text="{Binding Name}"   />
            </StackPanel>
        </DataTemplate>
 
        <DataTemplate x:Key="EditNetworkDataTemplate">
            <StackPanel>
                <TextBlock Text="BssID:"  />
                <TextBox Text="{Binding BssID}" />
            </StackPanel>
        </DataTemplate>
 
 
        <local:ListItemTemplateSelector x:Key="viewInListTemplateSelector"
              DefaultnDataTemplate="{StaticResource DefaultDataTemplate}"
              NoteDataTemplate="{StaticResource NetworkDataTemplate}" 
              SelectedNoteDataTemplate="{StaticResource SelectedNoteDataTemplate}" 
                                        />
        <local:ItemTemplateSelector x:Key="editTemplateSelector"
              DefaultnDataTemplate="{StaticResource DefaultDataTemplate}"
              NoteDataTemplate="{StaticResource EditNetworkDataTemplate}" 
                                        />
    </Window.Resources>
 
    
    <StackPanel HorizontalAlignment="Stretch" VerticalAlignment="Stretch" >
        <Grid  VerticalAlignment="Stretch" HorizontalAlignment="Stretch" >
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto"/>
                <ColumnDefinition Width="Auto"/>
            </Grid.ColumnDefinitions>
 
            <StackPanel Grid.Column="0" Orientation="Vertical">
 
                <ListBox
                    Height="300"
                    HorizontalAlignment="Left"
                    VerticalAlignment="Stretch" 
                    VerticalContentAlignment="Top"
                    x:Name="RecordsList"
                    ItemsSource="{Binding AllRecords}"
                    SelectedItem="{Binding SelectedRec}"
                    ItemTemplateSelector="{StaticResource viewInListTemplateSelector}"
                    />
 
            </StackPanel>
            <StackPanel Grid.Column="1" Orientation="Vertical">
                <ContentControl 
                    VerticalContentAlignment="Stretch" 
                    x:Name="TheRecord"
                    Content="{Binding SelectedRec}"
                    ContentTemplateSelector="{StaticResource ResourceKey=editTemplateSelector}">
                </ContentControl>
            </StackPanel>
        </Grid>
    </StackPanel>
</Window>

这是选择器的代码：

    public class ListItemTemplateSelector : DataTemplateSelector
    {
        public DataTemplate DefaultnDataTemplate { get; set; }
        public DataTemplate NoteDataTemplate { get; set; }
        public DataTemplate SelectedNoteDataTemplate { get; set; }
 
        public override DataTemplate SelectTemplate(object item, DependencyObject container)
        {
            if (null == item)
                return DefaultnDataTemplate;
            var lb = container as ListBox;
            if (item == lb.SelectedItem)
                return SelectedNoteDataTemplate;
            else
                return NoteDataTemplate;
        }
    }

一开始我调用了SelectTemplate（），但容器从不指向我的ListBox。而不是它，它指向ContentPresenter，我没想到这里。如何让SelectTemplate（）为列表框选择正确的模板？

Upon start I get SelectTemplate() called, but container never points to my ListBox. Instead of it, it points at ContentPresenter which I didn't expect here. How can I make SelectTemplate() select a correct template for the Listbox?

推荐答案

Hi Senglory，

Hi Senglory,

根据根据你的描述，你可能在var lb = container中有一些问题作为ListBox，它显示ib为null，

According to your description, you may have some issue in var lb = container as ListBox, it show that the ib is null,

所以如果你想获得ListBox，你可以使用以下代码：

so if you want to get ListBox, you can use the following code:

 Window window = System.Windows.Application.Current.MainWindow;
                ListBox list = window.FindName("RecordsList") as ListBox;

这意味着你想要在更改选择li ListBox时更改模板，你可以看一下下面的帖子，做到这一点。

It means that you want to change Template when you change selection li ListBox, you can take a look the following thread, do this in style.

https://stackoverflow.com/questions/146269/change-wpf-datatemplate-for-listbox-item-if-selected

最好的问候，

Cherry

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