WPF - Filtering/Searching multiple collection views within a treeview

I have a treeview that is bound to a collection and each item in the collection is bou开发者_运维技巧nd to another collection. (using hierachle data templates)

I would like to use the collection view .Filter event handler to search the tree. The problem is that I need multiple collection views.

What would be the best way to filter the tree view items for example by a search word? I can do this with a single binding of a collection, but once there are collections within collections I have trouble.

The easiest way I found to do this is create a SearchFilter Property

     public string SearchFilter
    {
        get { return _searchFilter; }
        set
        {
            _searchFilter = value;
            OnPropertyChanged("MyTreeViewBoundCollection");
        }
    }

You bind the search filter to a text box, and everytime the search text box changes you notify that the collection has changed

            <TextBox Text="{Binding Path=TemplateDataSchema.SearchFilter, UpdateSourceTrigger=PropertyChanged}"/>

Once the change has occured on the SearchFilter, The WPF binding system will requery the Collection Property, which can then be filtered down

 public ObservableCollection<Category> MyTreeViewBoundCollection
    {
        get {
            if (_searchFilter.Trim().Length < 1)
                return myObject.Categories;
            else
            {
                ObservableCollection<Category> cats = new ObservableCollection<Category>();
                string searchText = _searchFilter.ToLower().Trim();
                foreach (Category cat in myObject.Categories)
                {
                    Category tmpCat = new Category(cat.CategoryName);
                    foreach (Field field in cat.Fields)
                    {
                        if (field.DataDisplayName.ToLower().Contains(searchText))
                            tmpCat.Fields.Add(field);
                    }
                    if (tmpCat.Fields.Count > 0)
                        cats.Add(tmpCat);
                }

                return cats;
            }
        }
    }

This will only return the filter collection.