BInding textColor in Xamarin - xamarin

Question

In a Xamarin app I’m trying to bind a textcolor with a property in Message model.
public class Message : INotifyPropertyChanged
{
public string text { get; set; }
public Color color { get; set; }
public event PropertyChangedEventHandler PropertyChanged;
}
The task is, when I click on a label in a collectionview the text should change to Gray.
I can change the color in the ObservableCollection:
this.messages = new ObservableCollection();
(that’s works, and if I delete an entry in the ObservableCollection the screen updates)
But when I change the color in the message model, the screen doesn’t update.
I use MVVMhelpers, and I would like to use that to solve the problem, if possible.
best regards..

Answer 1

You could change the item color to gray when you click the item to triger the SelectionChanged event of CollectionView.
Xaml:
<CollectionView ItemsSource="{Binding messages}" SelectionMode="Single" SelectionChanged="CollectionView_SelectionChanged">
<CollectionView.ItemTemplate>
<DataTemplate>
<Label Text="{Binding text}" TextColor="{Binding color}"></Label>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
Code behind:
public partial class Page2 : ContentPage
{
public ObservableCollection<Message> messages { get; set; }
public Page2()
{
InitializeComponent();
messages = new ObservableCollection<Message>()
{
new Message(){ text="A", color="Red"},
new Message(){ text="B", color="Red"},
new Message(){ text="C", color="Red"},
};
this.BindingContext = this;
}
private void CollectionView_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
var previousItem = e.PreviousSelection.FirstOrDefault() as Message;
var currentItem = e.CurrentSelection.FirstOrDefault() as Message;
currentItem.color = "Gray";
if (previousItem!=null)
{
previousItem.color = "Red";
}
}
}
public class Message : INotifyPropertyChanged
{
private string _text;
public string text
{
get
{
return _text;
}
set
{
_text = value;
OnPropertyChanged("text");
}
}
private string _color;
public string color
{
get
{
return _color;
}
set
{
_color = value;
OnPropertyChanged("color");
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = "")
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}

Answer 2

super, great thanks.
I should also add
<DataTemplate x:DataType="{x:Type Models:Message}">