WPF - Good Way to take a list to a Tree

c#, list, listview, tree, wpf

Solution

This will take your list of strings and turn it into a tree suitable for viewing with TreeView as you described:

public IList BuildTree(IEnumerable<string> strings)
{
  return
    from s in strings
    let split = s.Split("/")
    group s by s.Split("/")[0] into g  // Group by first component (before /)
    select new
    {
      Name = g.Key,
      Children = BuildTree(            // Recursively build children
        from s in grp
        where s.Length > g.Key.Length+1
        select s.Substring(g.Key.Length+1)) // Select remaining components
    };
}

This will return a tree of anonymous types, each containing a Name property and a Children property. This can be bound directly to the `TreeView` by specifying a `HierarchicalDataTemplate` with `ItemsSource="{Binding Children}"` and content consisting of a `<TextBlock Text="{Binding Name}">` or similar.

Alternatively you could define a tree node class in code if you want additional members or semantics. For example, given this node class:

public class Node 
{
  public string Name { get; set; } 
  public List<Node> Children { get; set; } 
}

your BuildTree function would be slightly different:

public List<Node> BuildTree(IEnumerable<string> strings)
{
  return (
    from s in strings
    let split = s.Split("/")
    group s by s.Split("/")[0] into g  // Group by first component (before /)
    select new Node
    {
      Value = g.Key,
      Children = BuildTree(            // Recursively build children
        from s in grp
        where s.Length > g.Key.Length+1
        select s.Substring(g.Key.Length+1)) // Select remaining components
    }
    ).ToList();
}

Again this can be bound directly using a `HierarchicalDataTemplate`. I generally use the first solution (anonymous types) unless I want to do something special with the tree nodes.

Problem

I have a list that looks like this: ``` Base/Level1/Item1 Base/Level1/Item2 Base/Level1/Sub1/Item1 Base/Level2/Item1 Base/Level3/Sub1/Item1 ``` I would like an easy way put that into a ListView. (Ie similar to this) ``` Base | +->Level1 | | | +=Item1 | +=Item2 | | | +->Sub1 | | | +=Item1 | +->Level2 | | | +=Item1 | +->Level3 | +->Sub1 | +=Item1 ``` Is there an established way to make this kind of conversion or do I just need to roll my own parser? (In case it may be relevant the real items in my code are TFS Iteration Paths.)

Original source