Bind treeview to datatable

Question

Hi All

I'm a bit of a noob at WPF and an extreme noob at WPF databinding, so please bear with me.

I have a datatable with some data in it, such as the following:

Column1	Column2	Column3
a	a1	a1a
a	a1	a1b
a	a2	a2a
a	a2	a2b
b	b1	b1a
b	b1	b1b
b	b2	b2a
b	b2	b2b

I want to bind it to a treeview so it's displayed something like this:

-a
	-a1
		a1a
		a1b
	+a2
-b
	+b1
	+b2

I've tried working out the hierarchical datatemplate approach, but to no avail.

I'm working in visual basic express 2008

Can anyone help?

Ta

Answer 1

Hi,

There're many ways to do this,  the easiest way is adding items to the TreeView recursively. However, to recursively add items to the TreeView, I would recommend you change the table structure to something like this:

ID               int
Parent         int    nullable
Description   varchar

void Window1_Loaded(object sender, RoutedEventArgs e)

        {

            DataTable dt = new DataTable("data");

            dt.Columns.Add("id", typeof(int));

            dt.Columns.Add("ParentId", typeof(int));

            dt.Columns.Add("description");

 

            dt.Rows.Add(1, null, "a");

            dt.Rows.Add(2, null, "b");

            dt.Rows.Add(3, 1, "a1");

            dt.Rows.Add(4, 1, "a2");

            dt.Rows.Add(5, 2, "b1");

            dt.Rows.Add(6, 2, "b2");

            dt.Rows.Add(7, 3, "a1a");

            dt.Rows.Add(8, 3, "a1b");

            dt.Rows.Add(9, 4, "a2a");

            dt.Rows.Add(10, 4, "a2b");

            dt.Rows.Add(11, 5, "b1a");

            dt.Rows.Add(12, 5, "b2a");

            dt.Rows.Add(13, 6, "b1b");

            dt.Rows.Add(14, 6, "b2b");

 

            //Use a DataSet to manage the data

            DataSet ds = new DataSet();

            ds.Tables.Add(dt);

 

            //add a relationship

            ds.Relations.Add("rsParentChild", ds.Tables["data"].Columns["id"],

                ds.Tables["data"].Columns["ParentId"]);

 

            foreach (DataRow dr in ds.Tables["data"].Rows)

            {

                if (dr["ParentId"] == DBNull.Value)

                {

                    TreeViewItem root = new TreeViewItem();

                    root.Header = dr["description"].ToString();

                    treeView1.Items.Add(root);

                    PopulateTree(dr, root);

                }

            }

        }

 

 

        public void PopulateTree(DataRow dr, TreeViewItem pNode)

        {

            foreach (DataRow row in dr.GetChildRows("rsParentChild"))

            {

                TreeViewItem cChild = new TreeViewItem();

                cChild.Header = row["description"].ToString();

                pNode.Items.Add(cChild);

                //Recursively build the tree

                PopulateTree(row, cChild);

            }

        }

 

For other approaches, please check these aricles:

Binding a TreeView to a DataSet
http://joshsmithonwpf.wordpress.com/2007/05/05/binding-a-treeview-to-a-dataset/

TreeView on 2-level DataTable
http://social.msdn.microsoft.com/forums/en-US/wpf/thread/8ec80b7d-17e8-4d66-b8b0-07c8bfea6213/

Hierarchical Databinding in WPF
http://blogs.msdn.com/chkoenig/archive/2008/05/24/hierarchical-databinding-in-wpf.aspx


Best Regards,
Zhi-Xin

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Answer 2

Hi Zhi,

Many many thanks to you for you valuable reply. I am able to resolve my issue. Thanks again....