WPF。如何在代码后面的 ListViewItems 上添加不同的 styles？

Question

How can I apply different styles from source file to each ListViewItem in ListView, depends on thier object type (System.IO.DirectoryInfo and System.IO.FileInfo)?

There's simple XAML code that create ListView instance:

<Window x:Class="WPF_Research.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WPF_Research"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <StackPanel>
            <ListView Name="lvRoot"/>
        </StackPanel>
    </Grid>
</Window>

And there's code behind where the list fills:

public partial class MainWindow : Window
    {

        public MainWindow()
        {
            InitializeComponent();
            RefreshFolder();

        }

        public void RefreshFolder()
        {
            DirectoryInfo rootFolder = new DirectoryInfo(@"C:\");

            var rootDirs = rootFolder.GetDirectories();
            var rootFiles = rootFolder.GetFiles();

            foreach(var dir in rootDirs)
            {
                lvRoot.Items.Add(dir.Name);
                

            }
            foreach (var file in rootFiles)
            {
                lvRoot.Items.Add(file.Name);
            }
        }
    }

And resource file:

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Style x:Key="lviDirectories" TargetType="ListViewItem">
        <Setter Property="BorderBrush" Value="Black"/>
        <Setter Property="BorderThickness" Value="3"/>
        <Setter Property="FontSize" Value="18"/>
    </Style>
    <Style x:Key="lviFiles" TargetType="ListViewItem">
        <Setter Property="BorderBrush" Value="Red"/>
        <Setter Property="BorderThickness" Value="3"/>
        <Setter Property="FontSize" Value="16"/>
    </Style>
</ResourceDictionary>

I'm new to WPF.

Answer 1

You can do this as follows:

   <Window.Resources>
        <Style x:Key="lviDirectories" TargetType="ListViewItem">
            <Setter Property="BorderBrush" Value="Black"/>
            <Setter Property="BorderThickness" Value="3"/>
            <Setter Property="FontSize" Value="18"/>
        </Style>
        <Style x:Key="lviFiles" TargetType="ListViewItem">
            <Setter Property="BorderBrush" Value="Red"/>
            <Setter Property="BorderThickness" Value="3"/>
            <Setter Property="FontSize" Value="16"/>
        </Style>
    </Window.Resources>
    <Grid>
        <StackPanel VerticalAlignment="Center" Width="100">
            <ListView ItemsSource="{Binding MyCollection}">
                <ListView.ItemContainerStyleSelector>
                    <local:MyStyleSelector Style1="{StaticResource lviDirectories}" Style2="{StaticResource lviFiles}"/>
                </ListView.ItemContainerStyleSelector>
            </ListView>
        </StackPanel>
    </Grid>

    public class MainWindowViewModel
    {
        public ObservableCollection<string> MyCollection { get; set; } = new()
        {
            "a", "b", "c", "d", "e", "f", "g",
        };
    }

    public class MyStyleSelector : StyleSelector
    {
        public Style Style1 { get; set; }
        public Style Style2 { get; set; }

        public override Style SelectStyle(object item, DependencyObject container)
        {
            var s = (string)item;
            return s is "a" or "c" or "e" or "g" ? Style1 : Style2;
        }
    }

And this is the output: