Curd opration using MVVM in WPF

Question

1.00/5 (2 votes)

See more:

unable to get textbox values in viewmodel

[edit]Code block added - OriginalGriff[/edit]

What I have tried:

ui code-->

<Grid Margin="0,0,0,20">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
            <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>
        <ListView Name="UserGrid" Grid.Row="1" Margin="4,242,12,-21"  ItemsSource="{Binding Users}" Grid.RowSpan="2"  >
            <ListView.View>
                <GridView x:Name="grdTest">
                    <GridViewColumn Header="UserId" DisplayMemberBinding="{Binding UserId,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"  Width="50"/>
                    <GridViewColumn Header="First Name" DisplayMemberBinding="{Binding FirstName}"  Width="80" />
                    <GridViewColumn Header="Last Name" DisplayMemberBinding="{Binding LastName}" Width="100" />
                    <GridViewColumn Header="City" DisplayMemberBinding="{Binding City}" Width="80" />
                    <GridViewColumn Header="State" DisplayMemberBinding="{Binding State}" Width="80" />
                    <GridViewColumn Header="Country" DisplayMemberBinding="{Binding Country}" Width="100" />
                </GridView>
            </ListView.View>
        </ListView>
        <TextBox Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="80,7,0,0" Name="txtUserId" VerticalAlignment="Top" Width="178" Text="{Binding ElementName=UserGrid,Path=SelectedItem.UserId,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
        <TextBox Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="80,35,0,0" Name="txtFirstName" VerticalAlignment="Top" Width="178" Text="{Binding ElementName=UserGrid,Path=SelectedItem.FirstName,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
        <TextBox Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="80,62,0,0" Name="txtLastName" VerticalAlignment="Top" Width="178" Text="{Binding ElementName=UserGrid,Path=SelectedItem.LastName,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
        <Label Content="UserId" Grid.Row="1" HorizontalAlignment="Left" Margin="12,12,0,274" />
        <Label Content="Last Name" Grid.Row="1" Height="28" HorizontalAlignment="Left" Margin="12,60,0,0"  VerticalAlignment="Top" />
        <Label Content="First Name" Grid.Row="1" Height="28" HorizontalAlignment="Left" Margin="12,35,0,0" VerticalAlignment="Top" />
        <Button Content="Update" Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="184,199,0,0"  VerticalAlignment="Top" Width="95"
                Command="{Binding UpdateCommand,Source={StaticResource VM}}"  />
        <TextBox Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="80,87,0,0"  VerticalAlignment="Top" Width="178" Text="{Binding SelectedItem.City, ElementName=UserGrid,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
        <Label Content="Country" Grid.Row="1" Height="28" HorizontalAlignment="Left" Margin="12,141,0,0"  VerticalAlignment="Top" />
        <TextBox Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="80,150,0,0"  VerticalAlignment="Top" Width="178" Text="{Binding SelectedItem.Country, ElementName=UserGrid,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
        <Label Content="City" Grid.Row="1" Height="28" HorizontalAlignment="Left" Margin="12,86,0,0"  VerticalAlignment="Top" />
        <TextBox Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="80,115,0,0" VerticalAlignment="Top" Width="178" Text="{Binding SelectedItem.State, ElementName=UserGrid,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
        <Label Content="State" Grid.Row="1" Height="28" HorizontalAlignment="Left" Margin="12,113,0,0"  VerticalAlignment="Top" />
        <Button Content="Save" HorizontalAlignment="Left" Margin="80,199,0,0" Grid.Row="1" VerticalAlignment="Top" Width="99"
                Command="{Binding SaveCommand,Source={StaticResource VM}}" />
        <Button Content="Delete" HorizontalAlignment="Left" Margin="297,199,0,0" Grid.Row="1" VerticalAlignment="Top" Width="80" Command="{Binding DeleteCommand,Source={StaticResource VM}}" />
        <Button Content="Canceal" Command="{Binding CancealComand,Source={StaticResource VM}}"
                HorizontalAlignment="Left" Margin="394,199,0,0" Grid.Row="1" VerticalAlignment="Top" Width="74"/>
    </Grid>

Model Class:-

C#

public class User : INotifyPropertyChanged
    {
        private int userId;
        private string firstName;
        private string lastName;
        private string city;
        private string state;
        private string country;

        public int UserId
        {
            get
            {
                return userId;
            }
            set
            {
                userId = value;
                OnPropertyChanged("UserId");
            }
        }
        public string FirstName
        {
            get
            {
                return firstName;
            }
            set
            {
                firstName = value;
                OnPropertyChanged("FirstName");
            }
        }
        public string LastName
        {
            get
            {
                return lastName;
            }
            set
            {
                lastName = value;
                OnPropertyChanged("LastName");
            }
        }
        public string City
        {
            get
            {
                return city;
            }
            set
            {
                city = value;
                OnPropertyChanged("City");
            }
        }
        public string State
        {
            get
            {
                return state;
            }
            set
            {
                state = value;
                OnPropertyChanged("State");
            }
        }
        public string Country
        {
            get
            {
                return country;
            }
            set
            {
                country = value;
                OnPropertyChanged("Country");
            }
        }


        #region INotifyPropertyChanged Members
        public event PropertyChangedEventHandler PropertyChanged;
        private void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
        #endregion
    }

ViewModel Class:-
 private ObservableCollection<user> _UsersList;
        public UserViewModel()
        {
            

            getUSerList();
        }
        public ObservableCollection<user> Users
        {
            get { return _UsersList; }
            set { _UsersList = value; }
        }
         #region SaveCommand
        private ICommand saveCommand;
        public ICommand SaveCommand
        {
            get
            {
                if (saveCommand == null)
                {
                    saveCommand = new RelayCommand(SaveExecuted, CanSaveExecute);
                }
                return saveCommand;
            }

        }

        public bool CanSaveExecute(object parameter)
        {
            // for save command 
            User _uuser=new User ();

            int str = _uuser.UserId;

            return true;
        }
        public void SaveExecuted(object parameter)
        {
            string str = userId;



            MessageBox.Show("Save Button clicked");
        }
        #endregion
  #region INotifyPropertyChanged

        public event PropertyChangedEventHandler PropertyChanged;
        public void NotifyPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
        #endregion

Posted 4-Aug-17 0:13am

Satya Praksh Mishra

Updated 10-Aug-17 13:44pm

OriginalGriff

v2

Add a Solution

Comments

Graeme_Grant 4-Aug-17 8:03am

Do you mean when you click the buttons nothing happens?

Foothill 4-Aug-17 11:27am

Could you change UpdateSourceTrigger=PropertyChanged in the textbox to UpdateSourceTrigger=SelectionChanged and see what happens? I am assuming that you want to display additional info about an item the user selects in the ListView.

2 solutions

Solution 1

{Binding ElementName=UserGrid,Path=SelectedItem.UserId,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}

ListView.SelectedItem is not a User. It is an Instance of ListViewItem (or somthing like this).
You should use SelectedValue instead of SelectedItem.
It also could be a good idea to add SelectedUser property to the UserViewModel and
1) bind SelectedValue of ListView to this property
2) bind your TextBoxes like {Binding SelectedUser.UserId,Mode=TwoWay}
In this case you will not use ElementName in binding. Binding by ElementName not a best choice.

Posted 10-Aug-17 12:10pm

Valerii Tereshchenko

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Graeme_Grant · Accepted Answer · 2017-08-10T13:44:00

Your code has a few issues in the Xaml that caused problems. It is alway a good idea to keep it as clean as possible to make it readable. So here is a revised version for you:

XML

<Window x:Class="WpfListViewEdit.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:WpfListViewEdit"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525" WindowStartupLocation="CenterScreen">

    <Window.DataContext>
        <local:UserViewModel/>
    </Window.DataContext>

    <Grid Margin="20">
        <Grid.Resources>
            <Style TargetType="Label">
                <Setter Property="HorizontalAlignment" Value="Right"/>
                <Setter Property="VerticalAlignment" Value="Center"/>
                <Setter Property="Margin" Value="0 0 4 0"/>
            </Style>
            <Style TargetType="TextBox">
                <Setter Property="HorizontalAlignment" Value="Stretch"/>
                <Setter Property="VerticalAlignment" Value="Bottom"/>
                <Setter Property="Margin" Value="0 4"/>
            </Style>
            <Style TargetType="Button">
                <Setter Property="Margin" Value="10 0"/>
                <Setter Property="Padding" Value="10 5"/>
            </Style>
        </Grid.Resources>

        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" />
            <ColumnDefinition Width="200" />
            <ColumnDefinition />
        </Grid.ColumnDefinitions>

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

        <Label Content="_Id"
               Target="{Binding ElementName=txtUserId}" />
        <TextBox Name="txtUserId" Grid.Column="1" 
                 Text="{Binding ElementName=UserGrid, Path=SelectedItem.UserId, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

        <Label Content="_First Name" Grid.Row="1"
               Target="{Binding ElementName=txtFirstName}" />
        <TextBox Name="txtFirstName" Grid.Row="1" Grid.Column="1" 
                 Text="{Binding ElementName=UserGrid, Path=SelectedItem.FirstName,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

        <Label Content="_Last Name" Grid.Row="2"
               Target="{Binding ElementName=txtLastName}" />
        <TextBox Name="txtLastName" Grid.Row="2" Grid.Column="1" 
                 Text="{Binding ElementName=UserGrid, Path=SelectedItem.LastName,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

        <Label Content="C_ity" Grid.Row="3"
               Target="{Binding ElementName=txtCity}" />
        <TextBox Name="txtCity" Grid.Row="3" Grid.Column="1" 
                 Text="{Binding ElementName=UserGrid, Path=SelectedItem.City, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

        <Label Content="S_tate" Grid.Row="4"
               Target="{Binding ElementName=txtState}"/>
        <TextBox Name="txtState" Grid.Row="4" Grid.Column="1"
                 Text="{Binding ElementName=UserGrid, Path=SelectedItem.State, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

        <Label Content="C_ountry" Grid.Row="5"
               Target="{Binding ElementName=txtCountry}" />
        <TextBox Name="txtCountry" Grid.Row="5" Grid.Column="1"
                 Text="{Binding ElementName=UserGrid, Path=SelectedItem.Country ,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

        <StackPanel Orientation="Horizontal" Grid.Row="6" Grid.ColumnSpan="3" Margin="0 10" HorizontalAlignment="Center">
            <Button Content="_Save"  Command="{Binding SaveCommand}" />
            <Button Content="_Update" Command="{Binding UpdateCommand}" />
            <Button Content="_Delete" Command="{Binding DeleteCommand}" />
            <Button Content="_Cancel" Command="{Binding CancelComand}"/>
        </StackPanel>

        <ListView Name="UserGrid" Grid.Row="7" ItemsSource="{Binding Users}" Grid.ColumnSpan="3"  >
            <ListView.View>
                <GridView x:Name="grdTest">
                    <GridViewColumn Header="UserId" DisplayMemberBinding="{Binding UserId}" Width="50"/>
                    <GridViewColumn Header="First Name" DisplayMemberBinding="{Binding FirstName}" Width="80" />
                    <GridViewColumn Header="Last Name" DisplayMemberBinding="{Binding LastName}" Width="100" />
                    <GridViewColumn Header="City" DisplayMemberBinding="{Binding City}" Width="80" />
                    <GridViewColumn Header="State" DisplayMemberBinding="{Binding State}" Width="80" />
                    <GridViewColumn Header="Country" DisplayMemberBinding="{Binding Country}" Width="100" />
                </GridView>
            </ListView.View>
        </ListView>

    </Grid>

</Window>

With these changes in place, the Window works as expected if (Mock) data is supplied. As you select rows in the listview, the TextBoxes reflect the selection; any changes made in the TextBoxes is reflected in the ListView; all in real time.

The layout seems to be upside-down. I would have expected the Listview to be at the top, buttons to Add, Edit, Delete to be with the ListView (side or bottom), and the edit pane (edit fields with Save & Cancel buttons) to appear (come into view) separated at the bottom or pop up in an edit window when one of the ListView buttons were used. Something like this:

XML

<Window x:Class="WpfListViewEdit.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:WpfListViewEdit"
        mc:Ignorable="d"
        Title="MainWindow" Height="480" Width="600" WindowStartupLocation="CenterScreen">

    <Window.DataContext>
        <local:UserViewModel/>
    </Window.DataContext>

    <Grid Margin="20">
        <Grid.Resources>
            <Style TargetType="Label">
                <Setter Property="HorizontalAlignment" Value="Right"/>
                <Setter Property="VerticalAlignment" Value="Center"/>
                <Setter Property="Margin" Value="0 0 4 0"/>
            </Style>
            <Style TargetType="TextBox">
                <Setter Property="HorizontalAlignment" Value="Stretch"/>
                <Setter Property="VerticalAlignment" Value="Bottom"/>
                <Setter Property="Margin" Value="0 4"/>
            </Style>
            <Style TargetType="Button">
                <Setter Property="Margin" Value="10 0 0 0"/>
                <Setter Property="Padding" Value="10 5"/>
            </Style>
        </Grid.Resources>
        <Grid.RowDefinitions>
            <RowDefinition MinHeight="140"/>
            <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>

        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition />
                <RowDefinition Height="Auto"/>
            </Grid.RowDefinitions>
            <ListView Name="UserGrid" ItemsSource="{Binding Users}" Grid.ColumnSpan="3"  >
                <ListView.View>
                    <GridView x:Name="grdTest">
                        <GridViewColumn Header="UserId" DisplayMemberBinding="{Binding UserId}" Width="50"/>
                        <GridViewColumn Header="First Name" DisplayMemberBinding="{Binding FirstName}" Width="80" />
                        <GridViewColumn Header="Last Name" DisplayMemberBinding="{Binding LastName}" Width="100" />
                        <GridViewColumn Header="City" DisplayMemberBinding="{Binding City}" Width="80" />
                        <GridViewColumn Header="State" DisplayMemberBinding="{Binding State}" Width="80" />
                        <GridViewColumn Header="Country" DisplayMemberBinding="{Binding Country}" Width="100" />
                    </GridView>
                </ListView.View>
            </ListView>

            <StackPanel Orientation="Horizontal" Grid.Row="1" Margin="0 10"
                        HorizontalAlignment="Right">
                <Button Content="_Add"  Command="{Binding AddCommand}" />
                <Button Content="_Update" Command="{Binding UpdateCommand}" />
                <Button Content="_Delete" Command="{Binding DeleteCommand}" />
            </StackPanel>
        </Grid>

        <GroupBox Header="EDIT DETAILS" Grid.Row="1" Padding="10">

            <Grid Grid.Row="1">
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="Auto" />
                    <ColumnDefinition Width="200" />
                    <ColumnDefinition />
                </Grid.ColumnDefinitions>
                <Grid.RowDefinitions>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="*"/>
                </Grid.RowDefinitions>

                <Label Content="_Id"
                       Target="{Binding ElementName=txtUserId}" />
                <TextBox Name="txtUserId" Grid.Column="1" IsReadOnly="True"
                         Text="{Binding ElementName=UserGrid, Path=SelectedItem.UserId, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

                <Label Content="_First Name" Grid.Row="1"
                       Target="{Binding ElementName=txtFirstName}" />
                <TextBox Name="txtFirstName" Grid.Row="1" Grid.Column="1" 
                         Text="{Binding ElementName=UserGrid, Path=SelectedItem.FirstName,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

                <Label Content="_Last Name" Grid.Row="2"
                       Target="{Binding ElementName=txtLastName}" />
                <TextBox Name="txtLastName" Grid.Row="2" Grid.Column="1" 
                         Text="{Binding ElementName=UserGrid, Path=SelectedItem.LastName,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

                <Label Content="C_ity" Grid.Row="3"
                       Target="{Binding ElementName=txtCity}" />
                <TextBox Name="txtCity" Grid.Row="3" Grid.Column="1" 
                         Text="{Binding ElementName=UserGrid, Path=SelectedItem.City, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

                <Label Content="S_tate" Grid.Row="4"
                       Target="{Binding ElementName=txtState}"/>
                <TextBox Name="txtState" Grid.Row="4" Grid.Column="1"
                         Text="{Binding ElementName=UserGrid, Path=SelectedItem.State, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

                <Label Content="C_ountry" Grid.Row="5"
                       Target="{Binding ElementName=txtCountry}" />
                <TextBox Name="txtCountry" Grid.Row="5" Grid.Column="1"
                         Text="{Binding ElementName=UserGrid, Path=SelectedItem.Country ,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

                <StackPanel Orientation="Horizontal" Grid.Row="6" Grid.ColumnSpan="3" Margin="0 10" HorizontalAlignment="Right">
                    <Button Content="_Save"  Command="{Binding SaveCommand}" />
                    <Button Content="_Cancel" Command="{Binding CancelComand}"/>
                </StackPanel>

            </Grid>
        </GroupBox>

    </Grid>
</Window>

Now the Window starts to make sense.

Lastly, the button won't work as you have not implemented your RelayCommand, well not in the code supplied.

UPDATE: Re-reading your question, I noticed that the above failed to answer the following:

Satya Praksh Mishra wrote:
unable to get textbox values in viewmodel

So, instead of binding the edit fields directly to the Listview, bind then and the ListView.SelectedItem to a property in the ViewModel.

In the following example, to keep code clean, I have bound the ViewModel's SelectedUser property to the GroupBox. Bindings Cascade from parent to child in XAML. So the Textboxes' DataContext is bound to the SelectedUser of the UserViewModel. Now we only need to bind to the properties of the SelectedUser property of type User.

Updated XAML:

XML

<Window x:Class="WpfListViewEdit.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:WpfListViewEdit"
        mc:Ignorable="d"
        Title="Manage Users" Height="480" Width="600" WindowStartupLocation="CenterScreen">

    <Window.DataContext>
        <local:UserViewModel/>
    </Window.DataContext>

    <Grid Margin="20">
        <Grid.Resources>
            <Style TargetType="Label">
                <Setter Property="HorizontalAlignment" Value="Right"/>
                <Setter Property="VerticalAlignment" Value="Center"/>
                <Setter Property="Margin" Value="0 0 4 0"/>
            </Style>
            <Style TargetType="TextBox">
                <Setter Property="HorizontalAlignment" Value="Stretch"/>
                <Setter Property="VerticalAlignment" Value="Bottom"/>
                <Setter Property="Margin" Value="0 4"/>
            </Style>
            <Style TargetType="Button">
                <Setter Property="Margin" Value="10 0 0 0"/>
                <Setter Property="Padding" Value="10 5"/>
            </Style>
        </Grid.Resources>
        <Grid.RowDefinitions>
            <RowDefinition MinHeight="140"/>
            <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>

        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition />
                <RowDefinition Height="Auto"/>
            </Grid.RowDefinitions>
            <ListView Name="UserGrid" Grid.ColumnSpan="3" 
                      ItemsSource="{Binding Users}" 
                      SelectedItem="{Binding SelectedUser}">
                <ListView.View>
                    <GridView x:Name="grdTest">
                        <GridViewColumn Header="UserId" DisplayMemberBinding="{Binding UserId}" Width="50"/>
                        <GridViewColumn Header="First Name" DisplayMemberBinding="{Binding FirstName}" Width="80" />
                        <GridViewColumn Header="Last Name" DisplayMemberBinding="{Binding LastName}" Width="100" />
                        <GridViewColumn Header="City" DisplayMemberBinding="{Binding City}" Width="80" />
                        <GridViewColumn Header="State" DisplayMemberBinding="{Binding State}" Width="80" />
                        <GridViewColumn Header="Country" DisplayMemberBinding="{Binding Country}" Width="100" />
                    </GridView>
                </ListView.View>
            </ListView>

            <StackPanel Orientation="Horizontal" Grid.Row="1" Margin="0 10"
                        HorizontalAlignment="Right">
                <Button Content="_Add"  Command="{Binding AddCommand}" />
                <Button Content="_Update" Command="{Binding UpdateCommand}" />
                <Button Content="_Delete" Command="{Binding DeleteCommand}" />
            </StackPanel>
        </Grid>

        <GroupBox Header="EDIT DETAILS" Grid.Row="1" Padding="10" DataContext="{Binding SelectedUser}">

            <Grid Grid.Row="1">
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="Auto" />
                    <ColumnDefinition Width="200" />
                    <ColumnDefinition />
                </Grid.ColumnDefinitions>
                <Grid.RowDefinitions>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="*"/>
                </Grid.RowDefinitions>

                <Label Content="_Id"
                       Target="{Binding ElementName=txtUserId}" />
                <TextBox Name="txtUserId" Grid.Column="1" IsReadOnly="True"
                         Text="{Binding UserId, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

                <Label Content="_First Name" Grid.Row="1"
                       Target="{Binding ElementName=txtFirstName}" />
                <TextBox Name="txtFirstName" Grid.Row="1" Grid.Column="1" 
                         Text="{Binding FirstName, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

                <Label Content="_Last Name" Grid.Row="2"
                       Target="{Binding ElementName=txtLastName}" />
                <TextBox Name="txtLastName" Grid.Row="2" Grid.Column="1" 
                         Text="{Binding LastName, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

                <Label Content="C_ity" Grid.Row="3"
                       Target="{Binding ElementName=txtCity}" />
                <TextBox Name="txtCity" Grid.Row="3" Grid.Column="1" 
                         Text="{Binding City, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

                <Label Content="S_tate" Grid.Row="4"
                       Target="{Binding ElementName=txtState}"/>
                <TextBox Name="txtState" Grid.Row="4" Grid.Column="1"
                         Text="{Binding State, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

                <Label Content="C_ountry" Grid.Row="5"
                       Target="{Binding ElementName=txtCountry}" />
                <TextBox Name="txtCountry" Grid.Row="5" Grid.Column="1"
                         Text="{Binding Country ,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

                <StackPanel Orientation="Horizontal" Grid.Row="6" Grid.ColumnSpan="3" Margin="0 10" HorizontalAlignment="Right">
                    <Button Content="_Save"  Command="{Binding SaveCommand}" />
                    <Button Content="_Cancel" Command="{Binding CancelComand}"/>
                </StackPanel>

            </Grid>
        </GroupBox>

    </Grid>
</Window>

Updated UserViewModel:

C#

internal class UserViewModel : INotifyPropertyChanged
{
    private User selectedUser;
    private ObservableCollection<User> _UsersList;

    public UserViewModel()
    {
        GetUserList();
    }

    private void GetUserList()
    {
        Users = new ObservableCollection<User>();
        for (int i = 0; i < 100; i++)
        {
            Users.Add(new User
            {
                UserId = 1000 + i,
                FirstName = $"FirstName {i}",
                LastName = $"LastName {i}",
                City = $"City {i}",
                State = $"State {i}",
                Country = $"Country {i}"
            });
        }
    }

    public ObservableCollection<User> Users { get; set; }

    public User SelectedUser
    {
        get { return selectedUser; }
        set
        {
            if (selectedUser != value)
            {
                selectedUser = value;
                NotifyPropertyChanged(nameof(SelectedUser));
            }
        }
    }

    #region SaveCommand

    // TO BE IMPLEMENTED...
    //private ICommand saveCommand;
    //public ICommand SaveCommand
    //{
    //    get
    //    {
    //        if (saveCommand == null)
    //        {
    //            saveCommand = new RelayCommand(SaveExecuted, CanSaveExecute);
    //        }
    //        return saveCommand;
    //    }
    //}

    //public bool CanSaveExecute(object parameter)
    //{
    //    // for save command 
    //    User _uuser = new User();

    //    int str = _uuser.UserId;

    //    return true;
    //}

    //public void SaveExecuted(object parameter)
    //{
    //    //string str = userId;
    //    MessageBox.Show("Save Button clicked");
    //}

    #endregion

    #region INotifyPropertyChanged

    public event PropertyChangedEventHandler PropertyChanged;
    public void NotifyPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }

    #endregion
}

Now the ListView.SelectedItem is visible to the UserViewModel.