Как добавлять, сохранять и загружать элементы в список в WPF

Я только что обновил вашу структуру (я использовал класс, просто по привычке), чтобы использовать автоматические значения свойств, которые доступны в последних версиях VS. Реализация свойств по умолчанию встроена вместе с вспомогательными полями. Он используется так же, как и раньше.

Вы находитесь на правильном пути с ObservableCollection, но вам необходимо реализовать INotifyPropertyChanged, добавив Event PropertyChanged и предоставив Sub OnPropertyChanged для создания события.

Настройте привязки к элементам управления и установите ItemsSource или ListView в свой ObservableList.

Чтобы сохранить импорт System.Text, чтобы вы могли использовать StringBuilder. Цикл по списку для создания строки для сохранения в текстовый файл.

Я не тратил время на то, чтобы XAML-окна выглядели красиво. Простите некрасивость.

Class MainWindow
    Public Songs As New ObservableCollection(Of Song)

    Protected Sub OnLoad(sender As Object, e As RoutedEventArgs)
        Songs.Add(New Song("Nirvana", "Smells Like Teen Spirit", "Open"))
        Songs.Add(New Song("John Lennon", "Imagine", "In Stock"))
        Songs.Add(New Song("U2", "One", "Unknown"))
        Songs.Add(New Song("Michael Jackson", "Billie Jean", "Open"))
        lvSongs.ItemsSource = Songs
    End Sub

    Private Sub BtnAdd_Click(sender As Object, e As RoutedEventArgs)
        Dim frm As New frmAdd
        frm.mainForm = Me 'send the instance of the current form to the new form
        frm.ShowDialog()
    End Sub

    Private Sub SaveList()
        Dim sb As New StringBuilder
        For Each item As Song In Songs
            sb.AppendLine($"{item.Artist}|{item.Title}|{item.Status}")
        Next
        'call sb.ToString and write it to a .txt file
    End Sub
End Class

XAML для основного окна

<Window x:Class = "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_BindComboBox"
        mc:Ignorable = "d"
        Title = "MainWindow" Height = "450" Width = "800">
    <Grid Loaded = "OnLoad"
          Name = "root">
        <Grid.RowDefinitions>
            <RowDefinition Height = "Auto"/>
            <RowDefinition Height = "*"/>

        </Grid.RowDefinitions>
        <ListView Margin = "10" Name = "lvSongs" Grid.Row = "0">
            <ListView.ItemTemplate>
                <DataTemplate>
                    <WrapPanel>
                        <TextBlock Text = "Name: " />
                        <TextBox x:Name = "txtArtist" 
                                 Text = "{Binding Artist, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" 
                                 FontWeight = "Bold"/>
                        <TextBlock Text = ", " />
                        <TextBlock Text = "Age: " />
                        <TextBox Text = "{Binding Title}" 
                                 FontWeight = "Bold" />
                        <TextBlock Text = " (" />
                        <TextBox Text = "{Binding Status}"  />
                        <TextBlock Text = ")" />
                    </WrapPanel>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
        <Button x:Name = "btnAdd" Grid.Row = "1" Height = "25" Width = "100" Content = "Add a Song" Click = "BtnAdd_Click"/>      
    </Grid>
</Window>

Класс песни

Public Class Song
    Implements INotifyPropertyChanged

    Public Property Artist() As String
    Public Property Title() As String
    Public Property Status() As String

    Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged

    Protected Sub OnPropertyChanged(ByVal name As String)
        RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(name))
    End Sub

    Public Sub New(art As String, Ttl As String, Stat As String)
        Artist = art
        Title = Ttl
        Status = Stat
    End Sub
End Class

Окно добавления

Public Class frmAdd

    Public mainForm As MainWindow

    Private Sub BtnAdd_Click(sender As Object, e As RoutedEventArgs)
        mainForm.Songs.Add(New Song(txtArtist.Text, txtTitle.Text, txtStatus.Text))
        ClearForm()
    End Sub

    Private Sub ClearForm()
        txtArtist.Clear()
        txtTitle.Clear()
        txtStatus.Clear()
    End Sub

End Class

Добавить окно XAML

<Window x:Class = "frmAdd"
        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_BindComboBox"
        mc:Ignorable = "d"
        Title = "frmAdd" Height = "172.641" Width = "307.547">
    <Grid >
        <Grid.RowDefinitions>
            <RowDefinition Height = "Auto"/>
            <RowDefinition Height = "Auto"/>
            <RowDefinition Height = "Auto"/>
            <RowDefinition Height = "*"/>
            <RowDefinition Height = "*"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width = "100"/>
            <ColumnDefinition Width = "Auto"/>
        </Grid.ColumnDefinitions>
        <TextBlock Grid.Column = "0" Grid.Row = "0" Text = "Artist" FontSize = "16" FontWeight = "Bold"/>
        <TextBox x:Name = "txtArtist" Grid.Column = "1" Grid.Row = "0" FontSize = "16" Width = "150" />
        <TextBlock Grid.Column = "0" Grid.Row = "1" Text = "Title" FontSize = "16" FontWeight = "Bold"/>
        <TextBox x:Name = "txtTitle" Grid.Column = "1" Grid.Row = "1" FontSize = "16" Width = "150"/>
        <TextBlock Grid.Column = "0" Grid.Row = "2" Text = "Status" FontSize = "16" FontWeight = "Bold"/>
        <TextBox x:Name = "txtStatus" Grid.Column = "1" Grid.Row = "2" FontSize = "16" Width = "150"/>
        <Button x:Name = "btnAdd" Grid.Column = "1" Grid.Row = "4" Content = "Add Song" Click = "BtnAdd_Click"/>
    </Grid>
</Window>

РЕДАКТИРОВАТЬ Требуемый импорт

Imports System.Collections.ObjectModel
Imports System.ComponentModel
Imports System.Text