Hi ,
Anyone please help me 
My textbox will show listview seleted item 
 
<TextBox Name="txt1" HorizontalAlignment="Left" Height="23" Margin="46,90,0,0" TextWrapping="Wrap"  Text="{Binding ElementName=_PList,Path=SelectedItem.FirstName,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"  VerticalAlignment="Top" Width="120" Grid.Column="1" Grid.RowSpan="2"/>
 
 if I modify like this I can add new item
<TextBox Name="txt1" HorizontalAlignment="Left" Height="23" Margin="46,90,0,0" TextWrapping="Wrap"  Text="{Binding Path=Firstname,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"  VerticalAlignment="Top" Width="120" Grid.Column="1" Grid.RowSpan="2"/>
 
my question is how to achieve both scenario in binding way
 
I want to connect First property to Firstname,Firstname is model class property
 
I have added below logic in my viewmodel 
 public string First
        {
            get { return _First; }
            set { SetProperty(ref this._First, value); }
        }
 
 public void AddPerson()
         {
           
            this.PersonMaster.Add(new Person()
            {
                
                FirstName=this.First              
            }
           ); 
        }