TreeView will not update after DataSource has been set to null

2 posts, 1 answers
  1. Randy
    Randy avatar
    19 posts
    Member since:
    Oct 2012

    Posted 15 Apr 2013 Link to this post

    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()
           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;
               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);
       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;
  2. Answer
    Peter avatar
    1148 posts

    Posted 18 Apr 2013 Link to this post

    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,
    the Telerik team
    WinForms Q1 2013 boasts PivotGrid, PDF Viewer, Chart enhancements and more. Check out all of the latest highlights.
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