It stores the path from the root to the node, in the FullPath property. To specify the exact node in the model, TreePath class is used. For example, see the default implementation of the ITreeModel interface – the TreeModel class. The most common is the StructureChanged event, which cause the TreeView to fully refresh the specified node (or empty, for the whole model). If you wish TreeView to dynamically track model changes, you need to use one of several events of the ITreeModel interface. IsLeaf method tells TreeView whether it should try to read child nodes of the specified parent. GetChildren should return the list of child nodes of the specified parent (empty for root nodes). It’s very simple, and you need to implement only two methods. IEnumerable GetChildren(TreePath treePath) The model is described by ITreeModelInterface: The view asks the model for details, if needed, and displays the changes. If the model changes, it notifies the view by firing corresponding events. The main idea of this pattern is to split the model (business object) from its visualization (control). I really like the Model-View pattern, and decided to use it in this control. The following screenshots illustrate the TreeViewAdv features: NET code - No WinAPI is used in this control. Drag & Drop highlighting - Dynamically highlight the drop position.Load on Demand - Lazy load of child nodes. Multicolumns - You can split the TreeView into several columns.Unlimited number of controls for each node - You can display three icons + a CheckBox + two Labels.Multiselection - Maybe the first limitation which you will find in the standard TreeView is that it’s not possible to select more then one node.Model-View architecture - Will be covered in a separate section of this article.These are the key features of the TreeViewAdv control: The architecture of this control comes mainly from the Java Swing component, with some modifications. I could not find an alternative TreeView control which is free and fully meets my needs, so finally I decided to write my own. But learning this control to do something more complex is not an easy job. It works pretty well if you only need basic features. Of course, the first thing you will do is to use the standard. For example this pattern is not great for browsing the entire set of items.Working on several different projects, I was needed to display and edit hierarchical data. Note: This may not be appropriate depending on your context and user's expectations, not to mention the organization of your data. It's popular in e-commerce environment where the user has a good idea what they are looking for but wants to see their choices in context of similar items - or rather, the company wants to show similar items in the same context.ĭepending on whether you have already collected other relevant information from the user, some facets can be pre-selected. With each facet selection, the effect of selecting other facets can be fed back into the other facet selection buttons. With faceted navigation, the user can pick what's important to them. I might be wrong but the pattern which you seem to be hinting at is that of faceted navigation.įaceted search or navigation is an increasingly popular method of organizing data that would otherwise be hierarchically displayed in a fixed structure.
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