Building a tag cloud in WPF

Question

I'm trying to build a tag cloud in WPF based on an existing implementation [Download Source]. I didn't understand completely the implementation and my problem is, that instead of having the FontSize binded to the number of items in a collection, I want to bind it to some other values contained in a class. So in this part here,

FontSize="{Binding Path=ItemCount, Converter={StaticResource CountToFontSizeConverter}}"

I want to bind the FontSize to something else. How do I do that? Where does ItemCount belong to?

Thanks

Answer 1

ItemCount belongs to the group inside the collection view that is generated from that Tag.

e.g. if i have a list

A A B B B C

And i group them i get:

Group A : ItemCount = 2
Group B : ItemCount = 3
Group C : ItemCount = 1

The whole point of a Tag-Cloud is to bind to that very property because you want to visualize how often a certain tag is used.

---

To respond to your comments, the bare-bones setup should be something like this:

<ItemsControl ItemsSource="{Binding Data}">
    <ItemsControl.Resources>
        <vc:CountToFontSizeConverter x:Key="CountToFontSizeConverter"/>
    </ItemsControl.Resources>
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <WrapPanel />
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding Name}" Margin="2"
                       FontSize="{Binding Count, Converter={StaticResource CountToFontSizeConverter}}"/>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>

I assume that your data-object class exposes the properties Name and Count, to make sure that the size changes as count goes up that data-object class needs to implement INotifyPropertyChanged, that is about all there is to it.

public class Tag : INotifyPropertyChanged
{
    private string _name = null;
    public string Name
    {
        get { return _name; }
        set
        {
            if (_name != value)
            {
                _name = value;
                OnPropertyChanged("Name");
            }
        }
    }

    private int _count = 0;
    public int Count
    {
        get { return _count; }
        set
        {
            if (_count != value)
            {
                _count = value;
                OnPropertyChanged("Count");
            }
        }
    }

    //...

    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged(string propertyName)
    {
        if (this.PropertyChanged != null)
        {
            this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}