Bind to a property and Element value - WPF binding - wpf

Question

I have a checkbox which is binded to a object's property "IsValidCustomer" and I have a listview that holds some customers.
Whenever My user selects any Customer in the list, I want the Checkbox Checked property to set to False that means my "IsValidCustomer" property also will set to False automatically. Is there any way of achieving this using WPF bindings?
Any help in this regard would be highly appriciated.
Regards
-Srikanth

Answer 1

First make sure that your view's Datacontext is set to a viewmodel that implements the INotifyPropertyChanged interface then add a SelectedCustomer property that will hold the selected Customer from the ListView,
Each time the SelectedCustomer is set, check its value and set the IsValidCustomer property
here the full code :
the View model
public class Customer
{
public String Name { get; set; }
public String Id { get; set; }
}
public partial class MainWindow : Window, INotifyPropertyChanged
{
private Customer _selectedCustomer;
public Customer SelectedCustomer
{
get
{
return _selectedCustomer;
}
set
{
if (_selectedCustomer == value)
{
return;
}
_selectedCustomer = value;
OnPropertyChanged();
IsValidCustomer = (_selectedCustomer == null);
}
}
private ObservableCollection<Customer> _listCustomers;
public ObservableCollection<Customer> ListCustomers
{
get
{
return _listCustomers;
}
set
{
if (_listCustomers == value)
{
return;
}
_listCustomers = value;
OnPropertyChanged();
}
}
private bool _isValidCustomer = false;
public bool IsValidCustomer
{
get
{
return _isValidCustomer;
}
set
{
if (_isValidCustomer == value)
{
return;
}
_isValidCustomer = value;
OnPropertyChanged();
}
}
public MainWindow()
{
InitializeComponent();
}
public event PropertyChangedEventHandler PropertyChanged;
[NotifyPropertyChangedInvocator]
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
}
and the view
<StackPanel>
<CheckBox Content="IsValidCustomer" IsChecked="{Binding IsValidCustomer,Mode=TwoWay}"></CheckBox>
<ListView ItemsSource="{Binding ListCustomers}" SelectedItem="{Binding SelectedCustomer,Mode=TwoWay}"></ListView>
</StackPanel>

Answer 2

I am sure you have something like this in your model :
private bool _IsValidCustomer;
public bool IsValidCustomer
{
get { return _IsValidCustomer; }
set
{
_IsValidCustomer= value;
PropertyChanged(this, new PropertyChangedEventArgs("IsValidCustomer"));
}
}
Set the Binding for that bool property.
<Style TargetType="ListViewItem">
<Setter Property="IsSelected" Value="{Binding IsValidCustomer, Converter={StaticResource InverseBooleanConverter}}"/>
</Style>
Your CheckBox will be bound to this also :
<CheckBox IsChecked="{Binding IsValidCustomer, Mode=TwoWay}"/>
So, i assume you start with that IsValidCustomer set to true. And on selecting each row, you want to set it to false.
You will need an inverse boolean converter for this:
public class InverseBooleanConverter: IValueConverter
{
#region IValueConverter Members
public object Convert(object value, Type targetType, object parameter,
System.Globalization.CultureInfo culture)
{
if (targetType != typeof(bool))
throw new InvalidOperationException("The target must be a boolean");
return !(bool)value;
}
public object ConvertBack(object value, Type targetType, object parameter,
System.Globalization.CultureInfo culture)
{
throw new NotSupportedException();
}
#endregion
}