How do I make my listbox update when I click delete ?

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I have a ListBox which when I select an Item then click delete button the changes do not show immediately until I exit the app then start it up again. The changes reflect only when I have done that. Same goes for my saving button on the second window when I click save my listbox does not update the newly added Item until I exit the app and back to it again that is when I Will see what I have added.

What I have tried:

ViewModel for my first MainWindow

using GalaSoft.MvvmLight;
using GalaSoft.MvvmLight.Command;
using PhoneBook.View;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.IO;
using System.Linq;

namespace PhoneBook.ViewModel
{
    class MainWindowViewModel : ViewModelBase
    {
        #region Constructor
        public MainWindowViewModel()
        {
            ReadTextFile();
        }

        #endregion
        #region Properties
        public const string MyListPropertyName = "ListBox";
        private ObservableCollection<string> _contactDetails = null;
        public ObservableCollection<string> ContactDetails
        {
            get
            {
                return _contactDetails = _contactDetails ?? new ObservableCollection<string>();
            }
            set
            {
                if (_contactDetails == value)
                {
                    return;
                }
                RaisePropertyChanged(MyListPropertyName);
                _contactDetails = value;
                RaisePropertyChanged(MyListPropertyName);
            }
          
          
        }
        private string _selectedContact = null;
        public string SelectedContact
        {
            get
            {
                return _selectedContact;
            }
            set
            {
                if (_selectedContact != null)
                {
                    return;
                }
                _selectedContact = value;
                RaisePropertyChanged();
            }
        }



        #endregion

        #region Method


        string FileName = (@"C: \Users\StanleyM\Desktop\PhoneBook\PhoneBook\bin\Debug\Personal.text");
        private void DeleteSelectedItemListBox()
        {

            var deletingNumber = ContactDetails.IndexOf(SelectedContact);
            var allLines = File.ReadAllLines(FileName).ToList();
            allLines.RemoveAt(deletingNumber);
            File.WriteAllLines(FileName, allLines.ToArray());


            RaisePropertyChanged(propertyName: "ListBox");

        }

        public void ReadTextFile()
        {
            string FileName = (@"C: \Users\StanleyM\Desktop\PhoneBook\PhoneBook\bin\Debug\Personal.text");
            StreamReader streamReader = new StreamReader(FileName);
            string line = "";
            int Counter = 0;
            while ((line = streamReader.ReadLine()) != null)
            {
                Counter++;
                ContactDetails.Add(item: line);
            }
            RaisePropertyChanged("ListBox");
        }

        private void PopUpWindow()
        {
            AddEditView PopUp = new AddEditView();
            PopUp.ShowDialog();

        }


        #endregion
        #region RelayCommand

        private RelayCommand _addCommand = null;
        public RelayCommand AddCommand
        {
            get
            {
                return _addCommand = _addCommand ?? new RelayCommand(() => PopUpWindow());
            }
        }

        private RelayCommand _deleteCommand = null;
        public RelayCommand DeleteCommand
        {
            get
            {
                return _deleteCommand = _deleteCommand ?? new RelayCommand(() => DeleteSelectedItemListBox());
            }
        }


        #endregion
    }
}

First View

<Window x:Class="PhoneBook.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:PhoneBook"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
    
    <Window.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="/PhoneBook;component/Resource/Resource.xaml"></ResourceDictionary>
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Window.Resources>
    <Border BorderThickness="5" BorderBrush="AliceBlue" Background="AntiqueWhite">
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="*"/>
                <ColumnDefinition Width="*"/>
            </Grid.ColumnDefinitions>

            <Grid.RowDefinitions>
                <RowDefinition Height="25" />
                <RowDefinition Height="*" />

            </Grid.RowDefinitions>
            <Label Grid.Row="0" Content="List of Clients" ></Label>
            <Border Grid.Row="1" BorderThickness="5" Background="Black">
                <ListBox SelectedItem="{Binding SelectedContact, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" 
                         ItemsSource="{Binding ContactDetails, UpdateSourceTrigger=PropertyChanged, NotifyOnSourceUpdated=True, Mode=TwoWay}" 
                         Grid.Row="1">
                </ListBox>
            </Border>

            <Button Grid.Row="1"
                    Grid.Column="1" Width="75"
                    Height="25" VerticalAlignment="Top"
                    Margin="100 10 0 0" HorizontalAlignment="Left"
                    Content="Add" Command="{Binding AddCommand}"></Button>
            <Button Grid.Row="1"
                    Grid.Column="1"
                    Width="75" Height="25"
                    VerticalAlignment="Top"
                    Margin="100 60 0 0"
                    HorizontalAlignment="Left"
                    Content="Delete"
                    x:Name="Deletebtn" Click="Deletebtn_Click"
                    Command="{Binding DeleteCommand}"></Button>
        </Grid>
    </Border>
</Window>

ViewModel For my second window

using GalaSoft.MvvmLight;
using GalaSoft.MvvmLight.Command;
using PhoneBook.Class;
using PhoneBook.View;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;

namespace PhoneBook.ViewModel
{
    class AddEditViewModel : ViewModelBase
    {
        #region Construtors
        public AddEditViewModel()
        {
            PopulateDropDown();
        }
        #endregion
        #region Properties
        private List<_Title> _titles = null;
        public List<_Title> Titles
        {
            get
            {
                return _titles = _titles ?? new List<_Title>();
            }
        }

        private _Title _selectedTitle = null;
        public _Title SelectedTitle
        {
            get
            {
                return _selectedTitle;
            }
            set
            {
                _selectedTitle = value;
                RaisePropertyChanged();
            }
        }

        private List<_Gender> _genders = null;
        public List<_Gender> Genders
        {
            get
            {
                return _genders = _genders ?? new List<_Gender>();
            
            }
        }

        private _Gender _selectedGender = null;
        public _Gender SelectedGender
        {
            get
            {
                return _selectedGender;
            }
            set
            {
                _selectedGender = value;
                RaisePropertyChanged();

            }
        }

        private string _firstName = null;
        public string FirstName
        {
            get
            {
                return _firstName;
            }
            set
            {
                _firstName = value;
                RaisePropertyChanged();
            }
        }


        private string _lastName = null;
        public string LastName
        {
            get
            {
                return _lastName;
            }
            set
            {
                _lastName = value;
                RaisePropertyChanged();
            }
        }

        private string _email = null;
        public string Email
        {
            get
            {
                return _email;
            }
            set
            {
                _email = value;
                RaisePropertyChanged();
            }
        }

        private int _phoneNumber;
        public int PhoneNumber
        {
            get
            {
                return _phoneNumber;
            }
            set
            {
                _phoneNumber = value;
                RaisePropertyChanged();
            }
        }

        
        #endregion

        #region Method
        private void CloseWindow()
        {
            AddEditView add = new AddEditView();
            add.Close();
        }

           

        private void SaveDetails()
        {
            string Title = "";
            string Gender = "";

            int number = 0000000000;
            if (SelectedTitle == null)
                {
                MessageBox.Show("Please select Title");
                }
                else if (FirstName == null)
                {
                    MessageBox.Show("Please input First Name");
                }
                else if (LastName == null)
                {
                    MessageBox.Show("Please input last Name");
                }
                else if (Email == null)
                {
                    MessageBox.Show("Please input emaill");
                }
                else if (PhoneNumber != number )
                {
                    MessageBox.Show("Only nunmbers allowed");
                }
                else if(SelectedGender == null)
                {
                    MessageBox.Show("Please select Gender");
                }
                else if (true)
                {
               
                foreach (var item in Titles)
                {
                    Title = item.Title = SelectedTitle.Title;
                }


                
                foreach (var item in Genders)
                {
                    Gender = item.Gender = SelectedGender.Gender;
                }

                StringBuilder builder = new StringBuilder();
                builder.AppendLine(string.Format("{0} {1} {2} {3} {4} {5}",Title, FirstName, LastName, Email, PhoneNumber, Gender));
                File.AppendAllText("Personal.text", builder.ToString());
                MessageBox.Show("Save", "Information");
                

                }
           

        }

        private void PopulateDropDown()
        {
            Titles.Add(new _Title { Title = "Mr" });
            Titles.Add(new _Title { Title = "Dr" });
            Titles.Add(new _Title { Title = "Miss" });
            Titles.Add(new _Title { Title = "Ms" });
            Titles.Add(new _Title { Title = "Sir" });

            Genders.Add(new _Gender { Gender = "Male" });
            Genders.Add(new _Gender { Gender = "Female" });
        }

        #endregion

        #region RelayCommands

        private RelayCommand _saveCommand = null;
        public RelayCommand SaveCommand
        {
            get
            {
                return _saveCommand = _saveCommand ?? new RelayCommand(() => SaveDetails());
            }
        }

        private RelayCommand _cancelCommand = null;
        public RelayCommand CancelCommand
        {
            get
            {
                return _cancelCommand = _cancelCommand ?? new RelayCommand(() =>  CloseWindow());
            }
        }
        #endregion
    }
}

Second View

<Window x:Class="PhoneBook.View.AddEditView"
        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:PhoneBook.View"
        mc:Ignorable="d"
        Title="AddEditView" Height="300" Width="300">
    <Window.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="/PhoneBook;component/Resource/Resource.xaml"></ResourceDictionary>
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Window.Resources>
    <Grid>
        <Border BorderBrush="Black" BorderThickness="5" Background="AntiqueWhite">
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*"/>
                </Grid.ColumnDefinitions>
                <Grid.RowDefinitions>
                    <RowDefinition Height="*"/>
                    <RowDefinition Height="*"/>
                    <RowDefinition Height="*"/>
                    <RowDefinition Height="*"/>
                    <RowDefinition Height="*"/>
                    <RowDefinition Height="*"/>
                    <RowDefinition Height="*"/>
                    <RowDefinition Height="*"/>
                </Grid.RowDefinitions>
                <Label Content="Title"></Label>
                <ComboBox Grid.Row="0"
                          Grid.Column="0"
                          Text="{Binding Title, Mode=OneWay, UpdateSourceTrigger=PropertyChanged}"
                          ItemsSource="{Binding Titles, UpdateSourceTrigger=PropertyChanged}"
                          SelectedItem="{Binding SelectedTitle, UpdateSourceTrigger=PropertyChanged}"
                          DisplayMemberPath="Title"
                          Margin="3" 
                          Width="100"
                          Height="25"/>
                <Label Grid.Row="1"  
                       Content="First name" 
                       VerticalAlignment="Center" />
                <TextBox Grid.Row="1" 
                         Width="100" 
                         Height="25" 
                         Text="{Binding FirstName}"/>
                <Label Grid.Row="2" 
                       Content="Last name" 
                       VerticalAlignment="Center" />
                <TextBox Grid.Row="2" 
                         Width="100" 
                         Height="25" 
                         Text="{Binding LastName}"/>
                <Label Grid.Row="3" 
                       Content="Email" 
                       VerticalAlignment="Center" />
                <TextBox Grid.Row="3"
                         Text="{Binding Email}"
                         Width="100" 
                         Height="25"/>
                <Label Grid.Row="4"
                       Content="Phone number" 
                       VerticalAlignment="Center" />
                <TextBox Grid.Row="4" 
                         Width="100" 
                         Height="25"
                         Text="{Binding PhoneNumber}"/>
                <Label Grid.Row="5" 
                       Content="Gender"></Label>
                <ComboBox Grid.Row="5"
                          Width="100" 
                          Height="25" 
                          Text="{Binding Gender, Mode=OneWay, NotifyOnTargetUpdated=True}"
                          ItemsSource="{Binding Genders}"
                          DisplayMemberPath="Gender"
                          SelectedItem="{Binding SelectedGender}"/>

                <Button Grid.Row="7"
                        Height="25" 
                        Width="75" 
                        Margin="100,0,0,0" 
                        Content="Cancel" 
                        Command="{Binding CancelCommand}"/>

                <Button 
                    Grid.Row="7" 
                    Height="25"
                    Width="75" 
                    Margin="0,0,100,0" 
                    Content="Save" 
                    Command="{Binding SaveCommand}"/>
            </Grid>
        </Border>
    </Grid>
</Window>

Posted 11-Sep-17 20:54pm

Stanley Mabunda

Updated 11-Sep-17 23:27pm

v2

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Comments

Graeme_Grant 12-Sep-17 5:00am

Duplicate of previous question with slightly different title: How to delete seleted item from a listbox using MVVM.[^]

1 solution

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Graeme_Grant · Answer 1 · 2017-09-11T23:27:00

Solution 1

I covered that in my last answer, use an ObservableCollection, not a List<T>. Here: How to delete seleted item from a listbox using MVVM.[^]

Posted 11-Sep-17 23:27pm

Graeme_Grant

Comments

Stanley Mabunda 12-Sep-17 5:37am

Its still not working even when I changed to ObservableCollection

Graeme_Grant 12-Sep-17 5:43am

"Its still not working" tells me nothing. I'm a WPF programmer and use it all the time. It works fine IF implemented correctly. NEVER re-new the collection as it will break the binding and stop working, ALWAYS use .Clear() instead.

Time for you to do some debugging.

Stanley Mabunda 12-Sep-17 5:48am

I am doing some Debugging. I think the problem is with the Delete Method and Save Method When I Debug I see that is raising property change but ListBox is not updating whenever I have deleted something or added something. My Data is stored and retrieved from a textfile. Or maybe it has to do With the structure of my textfile ?

Graeme_Grant 12-Sep-17 5:56am

If you peek at the ObservableCollection definition, you can see that it is wired up for binding:

namespace System.Collections.ObjectModel
{
    public class ObservableCollection<T> : Collection<T>, INotifyCollectionChanged, INotifyPropertyChanged
    {
        public event NotifyCollectionChangedEventHandler CollectionChanged;
        protected event PropertyChangedEventHandler PropertyChanged;
        protected virtual void OnCollectionChanged(NotifyCollectionChangedEventArgs e);
        protected virtual void OnPropertyChanged(PropertyChangedEventArgs e);
    }
}

But the List definition is not:

namespace System.Collections.Generic
{
    public class List<T> : IList<T>, ICollection<T>, IList, ICollection, IReadOnlyList<T>, IReadOnlyCollection<T>, IEnumerable<T>, IEnumerable
    {
    }
}

Stanley Mabunda 12-Sep-17 6:07am

Ooooh I see that.

Stanley Mabunda 12-Sep-17 6:08am

Can I send you my App so you can see what I mean?

Graeme_Grant 12-Sep-17 6:11am

No, you need to do the work from here.

Stanley Mabunda 12-Sep-17 6:16am

Okay.