Create Treeview from Datatable using

In this article we will learn that how to create TreeView control from datatable object in language.

This example requires one windows form with TreeView control named TreeView1.
First we create a datatable object and then we will bind treeview with node like this:

Bind treeview control with datatable

Public Function CreateDataTable() As DataTable
        Dim dataTable As New DataTable()
        ' The value in this column will display on the TreeNode
        ' The value in this column will identify its parentId 
        ' Fill the DataTable
        dataTable.Rows.Add("India", "New Delhi")
        dataTable.Rows.Add("India", "Mumbai")
        dataTable.Rows.Add("India", "Kolkata")
        dataTable.Rows.Add("India", "Noida")
        dataTable.Rows.Add("USA", "New York")
        dataTable.Rows.Add("USA", "Washington")
        dataTable.Rows.Add("USA", "")
        dataTable.Rows.Add("USA", "India")
        Return dataTable
    End Function

above datatable has data like this

Treeview after binding from datatable in

And now we will create TreeView from above datatable. This example also learn that how to create TreeView at runtime or how to bind TreeView nodes to TreeView control at runtime.

    Public Sub BuildTree(ByVal dt As DataTable, ByVal trv As TreeView, ByVal expandAll As [Boolean])
        ' Clear the TreeView if there are another datas in this TreeView
        Dim node As TreeNode
        Dim subNode As TreeNode
        For Each row As DataRow In dt.Rows
            'search in the treeview if any country is already present
            node = Searchnode(row.Item(0).ToString(), trv)
            If node IsNot Nothing Then
               'Country is already present
                subNode = New TreeNode(row.Item(1).ToString())
                'Add cities to country
                node = New TreeNode(row.Item(0).ToString())
                subNode = New TreeNode(row.Item(1).ToString())
                'Add cities to country
            End If
        If expandAll Then
            ' Expand the TreeView
        End If
    End Sub
    Private Function Searchnode(ByVal nodetext As String, ByVal trv As TreeView) As TreeNode
        For Each node As TreeNode In trv.Nodes
            If node.Text = nodetext Then
                Return node
            End If
    End Function

7 thoughts on “Create Treeview from Datatable using”

  1. Excellent! Thank you! This has explained and helped me understand the syntax much better than the microsoft example, which requires you use a dataarray for storing the indexes of Parent Nodes. I was thinking though, wouldn’t a Dictionary be quicker and more efficient for that rather than iterating through every node with the search function each time?

  2. FYI, your ‘Searchnode’ function doesn’t return a value on all of its code paths.

  3. Hi, I want to know if it could work for more layers of the tree, not only two layers

  4. hey I have most the code working, the private searchnode function isn’t working though. I have tried to change it to where it is not a function and can be ran from form1. Here is what I tried:

    For Each nodes As TreeNode In TreeView1.Nodes(0).Nodes

    If nodes.Text = nodes.Text Then
    End If

    but it does not remove the same named node, what am I doing wrong?

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