Problem updating object properties with data Binding

Question

I’m trying to update the properties of an object every time a character is added/removed from the textboxes but I’m not getting... I read several topics about databinding and everything seems to be OK... I’m using the MVVM standard with WPF

The model class:

namespace TagPort.Models
{
    public class EPMConnection
    {
        public string epmServerMachine { get; set; }    
        public string serverPort { get; set; }
        public string serverUser { get; set; }
        public string serverPwd { get; set; }     
    }
}

Viewmodel:

namespace TagPort.ViewModels
{
    class ConnectionViewModel : INotifyPropertyChanged
    {
        public EPMConnection epmConnection;
        public ConnectionViewModel()
        {
            epmConnection = new EPMConnection { epmServerMachine = "Tteste2" };
        }

        public event PropertyChangedEventHandler PropertyChanged;

        protected void RaisePropertyChanged([CallerMemberName] String propertyName = "")
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }



        public EPMConnection Connection
        {
           get { return epmConnection; }
           set
            {
                epmConnection = value;
            }
        }
        public string EpmServerMachine
        {
            get { return epmConnection.epmServerMachine; }
            set
            {
                if(epmConnection.epmServerMachine != value)
                {
                    epmConnection.epmServerMachine = value;
                    RaisePropertyChanged();
                }
            }
        }
       public string EpmServerPort
        {
            get { return epmConnection.serverPort; }
            set
            {
                if (epmConnection.serverPort != value)
                {
                    epmConnection.serverPort = value;
                    RaisePropertyChanged();
                }
            }

        }
        public string EpmServerUser
        {
            get { return epmConnection.serverUser; }
            set
            {
                if (epmConnection.serverUser != value)
                {
                    epmConnection.serverUser = value;
                    RaisePropertyChanged();
                }
            }

        }
        public string EpmServerPwd
        {
            get { return epmConnection.serverPwd; }
            set
            {
                if (epmConnection.serverPwd != value)
                {
                    epmConnection.serverPwd = value;
                    RaisePropertyChanged();
                }
            }
        }
        public string ConnectionToString()
        {
            string p1 = (" EpmServer:"+ EpmServerMachine + "\n EpmPort:" + EpmServerPort + " \n EpmUser:" + EpmServerUser + " \n EpmPwd" + EpmServerPwd + "");
            return p1;
        }
    }
}

This is View’s XAML:

   <UserControl.Resources>
    <local:ConnectionViewModel x:Key="ConnectionVM"/>
</UserControl.Resources>


<Grid DataContext="{StaticResource ConnectionVM}">
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="180"></ColumnDefinition>
        <ColumnDefinition Width="*"></ColumnDefinition>
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
        <RowDefinition Height="34"></RowDefinition>
        <RowDefinition Height="34"></RowDefinition>
        <RowDefinition Height="34"></RowDefinition>
        <RowDefinition Height="34"></RowDefinition>
        <RowDefinition Height="34"></RowDefinition>
    </Grid.RowDefinitions>
    <Label Content="EPM Sever Machine:" HorizontalAlignment="Left" VerticalAlignment="Center" Grid.Column="0" Grid.Row="0"/>
    <Label Content="EPM Server Port:" HorizontalAlignment="Left" VerticalAlignment="Center" Grid.Column="0" Grid.Row="1"/>
    <Label Content="EPM Server User:" HorizontalAlignment="Left" VerticalAlignment="Center" Grid.Column="0" Grid.Row="2"/>
    <Label Content="EPM Server Password:" HorizontalAlignment="Left" VerticalAlignment="Center" Grid.Column="0" Grid.Row="3"/>

    <TextBox TextWrapping="Wrap" Text="{Binding EpmServerMachine,UpdateSourceTrigger=PropertyChanged}" Grid.Column="1" Grid.Row="0" VerticalAlignment="Center" Height="23" Margin="0,0,4,0"/>
    <TextBox TextWrapping="Wrap" Text="{Binding EpmServerPort,UpdateSourceTrigger=PropertyChanged}" Grid.Column="1" Grid.Row="1" VerticalAlignment="Center" Height="23" Margin="0,0,4,0"/>
    <TextBox TextWrapping="Wrap" Text="{Binding EpmServerUser,UpdateSourceTrigger=PropertyChanged}" Grid.Column="1" Grid.Row="2" VerticalAlignment="Center" Height="23" Margin="0,0,4,0"/>
    <TextBox TextWrapping="Wrap" Text="{Binding EpmServerPwd,UpdateSourceTrigger=PropertyChanged}" Grid.Column="1" Grid.Row="3" VerticalAlignment="Center" Height="23" Margin="0,0,4,0"/>



    <Button Content="Test Connection" Grid.Column="1" Grid.Row="4" Width="Auto" HorizontalAlignment="Right" Height="23" VerticalAlignment="Bottom" Margin="0,0,4,0" Click="TestConnection_Click"/>

</Grid>

And here’s the CS view

public partial class EPMConnectionTab : UserControl
    {
        ConnectionViewModel _viewModel;
        public EPMConnectionTab()
        {
            InitializeComponent();
            _viewModel = new ConnectionViewModel();
            this.DataContext = _viewModel;
        }

        private void TestConnection_Click(object sender, RoutedEventArgs e)
        {

            MessageBox.Show(_viewModel.ConnectionToString());
        }

    }