Task in Model not updating ui - MVVM Approach

Question

Hi

I am at lost again, why is that the task in the model does not update the UI whereas without the task, the ui gets updated fine, I believe it is something to do with threading, my code below. I remember doing something similar with the task located at the view model and that was executing fine, however, I thought I should do this in my model instead of view model.

public class Machine : INotifyPropertyChanged  
    {  
        public Machine()  
        {  
              
            Dtimer = new DispatcherTimer();  
               CallDispatcherTimer();  
            
  
        }  
        private DateTime _mchCurrentTime;  
  
        public DateTime MchCurrentTime  
        {  
            get  
            {  
                 
                return _mchCurrentTime;  
            }  
            set  
            {  
                if (_mchCurrentTime != value)  
                {  
                    _mchCurrentTime = value;  
                    OnPropertyChanged("MchCurrentTime");  
                }  
  
            }  
        }  
  
  
        
          
  
        public DispatcherTimer Dtimer { get; set; }  
        public void CallDispatcherTimer()  
        {  
             
            Dtimer.Interval = TimeSpan.FromSeconds(1);  
            Dtimer.Tick += ExecuteList;  
            Dtimer.Start();  
        }  
  
  
      
        
  
        public void RetrieveCurrentDateTime()  
        {  
            MchCurrentTime = DateTime.Now;  
  
        }  
  
        public async void ExecuteList(object sender, EventArgs e)  
        {  
              
  
            Task task = new Task(new Action(RetrieveCurrentDateTime));  
            task.Start();  
            await task;  
  
        }  
  
  
  
  
        public event PropertyChangedEventHandler PropertyChanged;  
  
        public void OnPropertyChanged(string propertyName)  
        {  
            PropertyChangedEventHandler ph = PropertyChanged;  
            if (ph != null)  
                ph(this, new PropertyChangedEventArgs(propertyName));  
        }  
    }  

In my viewmodel, I am just creating an instance of the Machine.

Answer 1

I used the code below with your Model code and it should work fine. If there are any questions please let me know.
Xaml:

<Window.DataContext>  
        <local:MachineViewModel/>  
    </Window.DataContext>  
    <StackPanel Orientation="Horizontal" Margin="250,0,0,0">  
        <Label Content="Date" Width="45" Height="30"/>  
        <TextBox x:Name="txtboxdate" Width="100" Height="20" IsReadOnly="True" Background="#bc9d1b" Text="{Binding Path=Mch.MchCurrentTime, StringFormat=MM/dd/yyyy, Mode=OneWay}"/>  
        <Label Content="Time" Width="45" Height="30" Margin="40,0,0,0"/>  
        <TextBox x:Name="txtboxtime" Width="100" Height="20" IsReadOnly="True" Background="#bc9d1b" Text="{Binding Path=Mch.MchCurrentTime, StringFormat=hh:mm:ss.fff tt, Mode=OneWay}"/>  
    </StackPanel>  

ViewModel:

 public class MachineViewModel   
    {  
  
        public MachineViewModel()  
        {  
            _mch = new Machine();  
  
        }  
  
        private Machine _mch;  
  
        public Machine Mch  
        {  
            get  
            {  
                return _mch;  
            }  
            set  
            {  
                _mch = value;  
            }  
        }  
    }  

The result:

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