WPF binding CombobBoxItem base on property - wpf

Question

My View Model class:
class Student : INotifyPropertyChanged
{
private string name;
private bool isVisible;
public event PropertyChangedEventHandler PropertyChanged;
public string PersonName
{
get { return name; }
set
{
name = value;
OnPropertyChanged("PersonName");
}
}
public bool IsVisible
{
get { return isVisible; }
set
{
isVisible = value;
OnPropertyChanged("IsVisible");
}
}
}
My Students collection that store all my objects:
public ObservableCollection<Student> Students { get; set; }
XAML:
<ComboBox x:Name="cbStudents"
ItemsSource="{Binding Students}"
SelectionChanged="cbInterfaces_SelectionChanged"/>
So in some point i want to disappear several Students from my ComboBox so i just change IsVisible value to False.
Any idea how to do that using XAML ?

Answer 1

You can have your Students collection return only visible students.
//All students (visible and invisible)
ObservableCollection<Students> _AllStudents = GetAllStudentsFromDataSource();
//only visible students
ObservableCollection<Students> _VisibleStudents = new ObservableCollection<Students>();
foreach(var _s in _AllStudents.Where(x => x.IsVisible)){
_VisibleStudents.Add(_s);
}
//your property
public ObservableCollection<Student> Students { get{ return _VisibleStudents; } }
In the case of your check box toggling the visibility of students, your checkbox can be bound to a command like this:
<Checkbox IsChecked="{Binding IsCheckboxChecked}" Command={Binding ToggleStudents}" />
And your view model has an extra control for the checkbox toggle and the command:
bool _IsCheckboxChecked = false;
public bool IsCheckboxChecked {
get { return _IsCheckboxChecked;}
set {
if(_IsCheckboxChecked != value)
{
_IsCheckboxChecked = value;
}
}
}
public ICommand ToggleStudents
{
get;
internal set;
}
private void ToggleStudentsCommand()
{
ToggleStudents = new RelayCommand(ToggleStudentsExecute);
}
public void ToggleStudentsExecute()
{
_VisibleStudents.Clear();
if(_IsCheckboxChecked){
foreach(var _s in _AllStudents.Where(x => x.IsVisible)){
_VisibleStudents.Add(_s);
}
}
else
{
foreach(var _s in _AllStudents.Where(x => x.IsVisible == false)){
_VisibleStudents.Add(_s);
}
}
OnPropertyChanged("Students");
}
Your xaml doesn't need to change.