Question

Lets say I have the following values that I’m loading into a datagrid

ID  |  Desc
------------------------ 
32     Red Cat
33     Blue Dog
34     Red Dog
37     Green Zebra
42     Reddish Snake
47     Greenlike Gorilla

I want to group my values on my data grid by the beginning colour specified in description. So it’ll be like this

ID  |  Desc
----------------------------
Red:
 32     Red Cat
 34     Red Dog
 42     Reddish Snake
Blue:
 33     Blue Dog
Green:
 37     Green Zebra
 47     Greenlike Gorilla

I have this for my code behind :

PagedCollectionView pageView = new PagedCollectionView(IEnumerable<MyClass> main);
pageView.GroupDescriptions.Add(new PropertyGroupDescription("")); //?????
this.MyGrid.ItemsSource = pageView;

How would I specify the grouping parameters?

Answer 1

You can provide an IValueConverter to the GroupDescription. So use :

new PropertyGroupDescription("Color", new StringToColorConverter())

where StringToColorConverter converts the Desc property to the color string:

public class StringToColorConverter: IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if ((string)value == null) return null;
        return ((string)value).Split(new [] { ' ' }).FirstOrDefault();    
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

---

Alternate approach

If you’re able to modify the class, then you could add a simple derived property Color.

class MyClass
{
    public string Desc { get; set; }
    public int ID { get; set; }

    public string Color
    {
        get
        {
            return Desc.Split(new [] { ' ' }).FirstOrDefault();    
        }
    }
}

Then you can group on it.

new PropertyGroupDescription("Color")