How to draw binary tree view using WPF?

Question

I want to draw it like this Image :

I can draw a binary tree on console. I want to draw it using WPF. Here is my code which I write for console.

class Program
{
    static void Main(string[] args)
    {
        List<BinaryTreeData> myBinaryData = new List<BinaryTreeData>();
        myBinaryData.Add(new BinaryTreeData{ownID=1});
        myBinaryData.Add(new BinaryTreeData { parentID=1, ownID = 2 });
        myBinaryData.Add(new BinaryTreeData {  parentID=1,ownID = 3 });

        foreach (var item in myBinaryData)
        {
            Console.WriteLine("{0}------{1}", item.parentID, item.ownID);   
        }
    }
}

class BinaryTreeData : INotifyPropertyChanged
{
    private int _ownID;
    private int _parentID;

    public int ownID
    {
        get { return this._ownID; }
        set { this._ownID = value; this.onChange("ownID"); }
    }

    public int parentID
    {
        get { return this._parentID; }
        set { this._parentID = value;  this.onChange("parentID"); }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    private void onChange(string propertyName)
    {
        if (PropertyChanged!=null)
        {
            this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
} 

I can`t understand how can I do that.

Answer 1

Each of your tree nodes need to have a collection of children. If you want to limit it to a binary tree then you can limit your collection of children to a max capacity of 2 items.

I would recommend this tutorial as it will also show you how to achieve this with MVVM.

http://www.codeproject.com/KB/WPF/TreeViewWithViewModel.aspx

EDIT:

Since you have updated your post and it seems like you are looking for something different, I think you would be better off using a 3rd party solution instead of implementing your own.

Try looking at these solutions -

http://www.codeproject.com/KB/WPF/LayeredTreeDraw.aspx

http://www.codeproject.com/KB/WPF/CustomTreeViewLayout.aspx

Answer 2

So, I restructured your code according to my above comment. The BinaryTreeData now have a SubItems List. You'll have to adjust the namespace in XAML / local:BinaryTreeData and it should work.. Cheers !

BinaryTreeData:

  public class BinaryTreeData : INotifyPropertyChanged
  {
    private int _ownID;
    private int _parentID;

    public int ownID
    {
      get { return this._ownID; }
      set
      {
        this._ownID = value;
        this.onChange("ownID");
      }
    }

    private List<BinaryTreeData> _subitems = new List<BinaryTreeData>();

    public List<BinaryTreeData> Subitems
    {
      get { return _subitems; }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    private void onChange(string propertyName)
    {
      if (PropertyChanged != null)
      {
        this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
      }
    }
  }

XAML:

<TreeView x:Name="myTreeView">
  <TreeView.ItemTemplate>
    <HierarchicalDataTemplate DataType="{x:Type local:BinaryTreeData}" ItemsSource="{Binding Subitems}">
      <TextBlock  Text="{Binding Path=ownID}" />
    </HierarchicalDataTemplate>
  </TreeView.ItemTemplate>
</TreeView>

CodeBehind:

public MainWindow()
{
  InitializeComponent();

  List<BinaryTreeData> myBinaryData = new List<BinaryTreeData>();

  BinaryTreeData parent1 = new BinaryTreeData() { ownID = 1 };
  parent1.Subitems.Add(new BinaryTreeData { ownID = 2 });
  parent1.Subitems.Add(new BinaryTreeData { ownID = 3 });

  BinaryTreeData parent2 = new BinaryTreeData() { ownID = 4 };
  parent2.Subitems.Add(new BinaryTreeData { ownID = 5 });
  parent2.Subitems.Add(new BinaryTreeData { ownID = 6 });

  myBinaryData.Add(parent1);
  myBinaryData.Add(parent2);

  myTreeView.ItemsSource = myBinaryData;
}