TreeView will not update after DataSource has been set to null

[Randy]

When using an object-relational binding with the TreeView control, if the DataSource is set to something, set to null and then set to something again the tree will no longer update.

Here is a code sample:

1. Click Load - the base data appears in the tree.
2. Click Add - a new node appear in the tree.
3. Click Clear - all nodes are erased.
4. Click Load - base data is added back in and appears
5. Click Add - nothing happens...

public partial class Form1 : Form
   {
       BindingList<Thing> RootChildren;
       int currentId = 1;

       public Form1()
       {
           InitializeComponent();
       }

       private void buttonLoad_Click(object sender, EventArgs e)
       {
           radTreeView1.DataSource = null;
           RootChildren = new BindingList<Thing>();

           Thing t1 = new Thing(1, "One");
           Thing t2 = new Thing(2, "Two");
           Thing t3 = new Thing(3, "Three");
           Thing t4 = new Thing(4, "Four");
           currentId = 5;

           RootChildren.Add(t1);
           RootChildren.Add(t2);
           RootChildren.Add(t3);
           RootChildren.Add(t4);

           radTreeView1.DataSource = RootChildren;
           radTreeView1.ChildMember = @"Children\Children\Children\Children";
           radTreeView1.ValueMember = "Id";
           radTreeView1.DisplayMember = "Name";
       }

       private void buttonClear_Click(object sender, EventArgs e)
       {
           radTreeView1.DataSource = null;
       }

       private void buttonAdd_Click(object sender, EventArgs e)
       {
           Thing thing = new Thing(currentId, "NewThing" + currentId);
           RootChildren.Add(thing);
           currentId++;

           RootChildren.ResetBindings();
       }
   }

   public class Thing
   {
       public int Id { get; set; }
       public string Name { get; set; }
       public BindingList<Thing> Children = new BindingList<Thing>();

       public Thing() { }
       public Thing(int id, string name)
       {
           Id = id;
           Name = name;
       }
   }

[Peter]

Hi Randy,

Thank you for the attached project.

I was able to reproduce the described behavior. You should to reset the RadTreeView's ChildMember property when you reset the DataSource property:

radTreeView1.DataSource = null;
radTreeView1.ChildMember = "";

This will allow RadTreeView to create and associate new relation objects for the new data source.

I hope this helps.

All the best,
Peter
the Telerik team