Ok you only need to add these in your BindableTextBlock With your Original solution. What we do here is we add handler for when collection is changed (meaning new values are added), we only do that when the collection is set. So with the binding that you have in your xaml every change you make on the collection in the VM fires collection changed event in the textblock which in turn just appends values to the Inline.
private void CollectionChangedHandler(object sender, NotifyCollectionChangedEventArgs e)
{
Inlines.AddRange(e.NewItems);
}
private static void OnPropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
if (e.NewValue == null) return;
var textBlock = (BindableTextBlock)sender;
textBlock.InlineList.CollectionChanged += textBlock.CollectionChangedHandler;
}
BEFORE EDIT for history reasons
Ok I saw what's happening so first the explanation then an example.
So first some basic concepts about wpf:
In order to have your view notified for a change in bound variable in your ViewModel (or whatever that is DataContext at the moment) you have to either RaisePropertyChanged event with the name of the changed property or use something that's doing this somehow :) - like ObservableCollection.
So some use cases:
You have a property with field -> it is common practice to have it like this:
private ICollection<Inline> _inlineList;
public ICollection<Inline> InlineList
{
get
{
return _inlineList;
}
set
{
_inlineList = value;
RaisePropertyChanged("InlineList");
}
}
This ensures that when you set a new value to InlineList the view will be notified
Or in your case what I've used:
private ICollection<Inline> _inlineList;
public ICollection<Inline> InlineList
{
get { return _inlineList; }
set { Set(() => InlineList, ref _inlineList, value); }
}
If you check the description of Set method you'll see that it is setting the value and raising the property (and some more stuff)
You want to have automatic updates and use ObservableCollection -> I use it like this:
private ObservableCollection<ClientFilter> clientFilters;
public IEnumerable<ClientFilter> ClientFilters
{
get
{
if (this.clientFilters == null)
{
this.clientFilters = new ObservableCollection<ClientFilter>();
}
return this.clientFilters;
}
set
{
if (this.clientFilters == null)
{
this.clientFilters = new ObservableCollection<ClientFilter>();
}
SetObservableValues<ClientFilter>(this.clientFilters, value);
}
}
The method SetObservableValues is in my main ViewModel and is doing this:
public static void SetObservableValues<T>(
ObservableCollection<T> observableCollection,
IEnumerable<T> values)
{
if (observableCollection != values)
{
observableCollection.Clear();
foreach (var item in values)
{
observableCollection.Add(item);
}
}
}
This method ensures that if the reference to the obs collection is not the same it will clear the old one and reuse it, because when you bind you bind to the reference at common mistake is to then change the reference itself not the values, which in turn doesn't update anything on the UI and you think binding is broken :)
So If you want it to function normally you just add/remove to the Collection/Enumerable ClientFilters
Now the solution
So I'm not 100% sure what you want to achieve but here's what you could do in order to have your binding working
Your ViewModel
using GalaSoft.MvvmLight;
using GalaSoft.MvvmLight.Command;
using System.Collections.Generic;
using System.Windows;
using System.Windows.Documents;
namespace WpfApplication3.ViewModel
{
public class MainViewModel : ViewModelBase
{
public MainViewModel()
{
}
private ICollection<Inline> _inlineList;
public ICollection<Inline> InlineList
{
get { return _inlineList; }
set { Set(() => InlineList, ref _inlineList, value); }
}
public RelayCommand SendClicked
{
get
{
return new RelayCommand(() =>
{
InlineList = new List<Inline>
{
new Run("This is some bold text") { FontWeight = FontWeights.Bold },
new Run("Some more text"),
new Run("This is some text") { TextDecorations = TextDecorations.Underline }
};
});
}
}
}
}
Your custom control -> BindableTextBlock
using System.Collections.Generic;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
namespace WpfApplication3
{
public class BindableTextBlock : TextBlock
{
public ICollection<Inline> InlineList
{
get { return (ICollection<Inline>)GetValue(InlineListProperty); }
set { SetValue(InlineListProperty, value); }
}
public static readonly DependencyProperty InlineListProperty =
DependencyProperty.Register("InlineList", typeof(List<Inline>), typeof(BindableTextBlock), new UIPropertyMetadata(null, OnPropertyChanged));
private static void OnPropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
if (e.NewValue == null) return;
var textBlock = (BindableTextBlock)sender;
textBlock.Inlines.AddRange((ICollection<Inline>)e.NewValue);
}
}
}
Your XAML
On your Page or Window (depending on platform)
DataContext="{Binding Main, Source={StaticResource Locator}}"
Then inside
<StackPanel>
<Button Command="{Binding SendClicked}">SendClicked</Button>
<local:BindableTextBlock Background="Black" Foreground="AliceBlue"
Width = "Auto" Height="Auto"
InlineList="{Binding InlineList}"
>
</local:BindableTextBlock>
</StackPanel>
All assuming you have your ViewModelLocator from MVVM Light register your view model
using GalaSoft.MvvmLight.Ioc;
using Microsoft.Practices.ServiceLocation;
namespace WpfApplication3.ViewModel
{
public class ViewModelLocator
{
public ViewModelLocator()
{
ServiceLocator.SetLocatorProvider(() => SimpleIoc.Default);
SimpleIoc.Default.Register<MainViewModel>();
}
public MainViewModel Main
{
get
{
return ServiceLocator.Current.GetInstance<MainViewModel>();
}
}
public static void Cleanup()
{
}
}
}
ALTERNATIVE
Alternatively you could have your command like this:
public RelayCommand SendClicked
{
get
{
return new RelayCommand(() =>
{
_inlineList = new List<Inline>();
InlineList.Add(new Run("This is some bold text") { FontWeight = FontWeights.Bold });
InlineList.Add(new Run("Some more text"));
InlineList.Add(new Run("This is some text") { TextDecorations = TextDecorations.Underline });
RaisePropertyChanged("InlineList");
});
}
}
But you have to use the other option of defining the property as described at the beginning of my post.
You could do it in other ways of course.
Just one more advice -> It is considered bad practice and not in the spirit of MVVM to have UI elements in your view model, so change in architecture is strongly advised in this code IMO.
Post got too long (as usual), if you need aditional explanation please let me know.
Cheers and happy coding ;)
