Hi vsaklani,

I have created a sample which full fill your requirement you need to modify the code according to your need.

I have taken reference from below article.

Populate (Bind) ASP.Net TreeView with Parent Child relationship from database in ASP.Net

HTML

<div>
    <table>
        <tr>
            <td>
                <asp:TreeView ID="TreeView1" runat="server" ImageSet="XPFileExplorer" NodeIndent="15"
                    OnSelectedNodeChanged="TreeView1_SelectedNodeChanged">
                    <HoverNodeStyle Font-Underline="True" ForeColor="#6666AA" />
                    <NodeStyle Font-Names="Tahoma" Font-Size="8pt" ForeColor="Black" HorizontalPadding="2px"
                        NodeSpacing="0px" VerticalPadding="2px"></NodeStyle>
                    <ParentNodeStyle Font-Bold="False" />
                    <SelectedNodeStyle BackColor="#B5B5B5" Font-Underline="False" HorizontalPadding="0px"
                        VerticalPadding="0px" />
                </asp:TreeView>
            </td>
            <td>
                <asp:TreeView ID="TreeView2" runat="server" ImageSet="XPFileExplorer" NodeIndent="15">
                    <HoverNodeStyle Font-Underline="True" ForeColor="#6666AA" />
                    <NodeStyle Font-Names="Tahoma" Font-Size="8pt" ForeColor="Black" HorizontalPadding="2px"
                        NodeSpacing="0px" VerticalPadding="2px"></NodeStyle>
                    <ParentNodeStyle Font-Bold="False" />
                    <SelectedNodeStyle BackColor="#B5B5B5" Font-Underline="False" HorizontalPadding="0px"
                        VerticalPadding="0px" />
                </asp:TreeView>
            </td>
        </tr>
    </table>
</div>

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        this.PopulateTreeView(this.GetData("SELECT Id, Name FROM VehicleTypes"), 0, null);
    }
}

private void PopulateTreeView(DataTable dtParent, int parentId, TreeNode treeNode)
{
    foreach (DataRow row in dtParent.Rows)
    {
        TreeNode child = new TreeNode { Text = row["Name"].ToString(), Value = row["Id"].ToString() };
        if (parentId == 0)
        {
            TreeView1.Nodes.Add(child);
            PopulateTreeView(this.GetData("SELECT Id, Name FROM VehicleSubTypes WHERE VehicleTypeId = " + child.Value), int.Parse(child.Value), child);
        }
        else
        {
            treeNode.ChildNodes.Add(child);
        }
    }
}

private DataTable GetData(string query)
{
    DataTable dt = new DataTable();
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand(query))
        {
            using (SqlDataAdapter sda = new SqlDataAdapter())
            {
                cmd.CommandType = CommandType.Text;
                cmd.Connection = con;
                sda.SelectCommand = cmd;
                sda.Fill(dt);
            }
        }
        return dt;
    }

}

protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e)
{
    try
    {
        string parent = this.TreeView1.SelectedNode.Parent.Text;
        int parentId = Convert.ToInt32(this.TreeView1.SelectedNode.Parent.Value);
        string child = this.TreeView1.SelectedNode.Text;
        int childId = Convert.ToInt32(this.TreeView1.SelectedNode.Value);

        DataTable dtParent = new DataTable();
        dtParent.Columns.AddRange(new DataColumn[2] { new DataColumn("Id", typeof(int)), new DataColumn("Name") });
        dtParent.Rows.Add(parentId, parent);
        DataTable dtChild = new DataTable();
        dtChild.Columns.AddRange(new DataColumn[3] { new DataColumn("Id", typeof(int)), new DataColumn("Name"), new DataColumn("parentId") });
        dtChild.Rows.Add(childId, child, parentId);
        DuplicatePopulateTreeView(dtParent, dtChild);
    }
    catch (Exception ex)
    {
        ClientScript.RegisterClientScriptBlock(this.GetType(), "Alert", "alert('please select child node for copying')", true);
    }
}

private void DuplicatePopulateTreeView(DataTable dtParent, DataTable dtChild)
{
    for (int i = 0; i < dtParent.Rows.Count; i++)
    {
        TreeNode parentNode = new TreeNode { Text = dtParent.Rows[i]["Name"].ToString(), Value = dtParent.Rows[i]["Id"].ToString() };
        foreach (DataRow childRows in dtChild.Rows)
        {
            parentNode = TreeView2.FindNode(dtParent.Rows[i]["Id"].ToString());
            if (parentNode == null)
            {
                parentNode = new TreeNode { Text = dtParent.Rows[i]["Name"].ToString(), Value = dtParent.Rows[i]["Id"].ToString() };
                TreeView2.Nodes.Add(parentNode);
            }

            TreeNode childNode = new TreeNode { Text = childRows["Name"].ToString(), Value = childRows["Id"].ToString() };
            if (!NodeExists(parentNode, childRows["Name"].ToString()))
            {
                parentNode.ChildNodes.Add(childNode);
            }
        }
    }
}

private bool NodeExists(TreeNode node, string key)
{
    foreach (TreeNode subNode in node.ChildNodes)
    {
        if (subNode.Text == key)
        {
            return true;
        }
    }
    return false;
}

VB.Net

Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Me.PopulateTreeView(Me.GetData("SELECT Id, Name FROM VehicleTypes"), 0, Nothing)
    End If
End Sub

Private Sub PopulateTreeView(dtParent As DataTable, parentId As Integer, treeNode As TreeNode)
    For Each row As DataRow In dtParent.Rows
        Dim child As New TreeNode() With { _
         .Text = row("Name").ToString(), _
         .Value = row("Id").ToString() _
        }
        If parentId = 0 Then
            TreeView1.Nodes.Add(child)
            PopulateTreeView(Me.GetData("SELECT Id, Name FROM VehicleSubTypes WHERE VehicleTypeId = " + child.Value), Integer.Parse(child.Value), child)
        Else
            treeNode.ChildNodes.Add(child)
        End If
    Next
End Sub

Private Function GetData(query As String) As DataTable
    Dim dt As New DataTable()
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As New SqlConnection(constr)
        Using cmd As New SqlCommand(query)
            Using sda As New SqlDataAdapter()
                cmd.CommandType = CommandType.Text
                cmd.Connection = con
                sda.SelectCommand = cmd
                sda.Fill(dt)
            End Using
        End Using
        Return dt
    End Using
End Function

Protected Sub TreeView1_SelectedNodeChanged(sender As Object, e As EventArgs)
    Try
        Dim parent As String = Me.TreeView1.SelectedNode.Parent.Text
        Dim parentId As Integer = Convert.ToInt32(Me.TreeView1.SelectedNode.Parent.Value)
        Dim child As String = Me.TreeView1.SelectedNode.Text
        Dim childId As Integer = Convert.ToInt32(Me.TreeView1.SelectedNode.Value)

        Dim dtParent As New DataTable()
        dtParent.Columns.AddRange(New DataColumn(1) {New DataColumn("Id", GetType(Integer)), New DataColumn("Name")})
        dtParent.Rows.Add(parentId, parent)
        Dim dtChild As New DataTable()
        dtChild.Columns.AddRange(New DataColumn(2) {New DataColumn("Id", GetType(Integer)), New DataColumn("Name"), New DataColumn("parentId")})
        dtChild.Rows.Add(childId, child, parentId)
        DuplicatePopulateTreeView(dtParent, dtChild)
    Catch ex As Exception
        ClientScript.RegisterClientScriptBlock(Me.[GetType](), "Alert", "alert('please select child node for copying')", True)
    End Try
End Sub

Private Sub DuplicatePopulateTreeView(dtParent As DataTable, dtChild As DataTable)
    For i As Integer = 0 To dtParent.Rows.Count - 1
        Dim parentNode As New TreeNode() With { _
          .Text = dtParent.Rows(i)("Name").ToString(), _
          .Value = dtParent.Rows(i)("Id").ToString() _
        }
        For Each childRows As DataRow In dtChild.Rows
            parentNode = TreeView2.FindNode(dtParent.Rows(i)("Id").ToString())
            If parentNode Is Nothing Then
                parentNode = New TreeNode() With { _
                  .Text = dtParent.Rows(i)("Name").ToString(), _
                  .Value = dtParent.Rows(i)("Id").ToString() _
                }
                TreeView2.Nodes.Add(parentNode)
            End If

            Dim childNode As New TreeNode() With { _
              .Text = childRows("Name").ToString(), _
              .Value = childRows("Id").ToString() _
            }
            If Not NodeExists(parentNode, childRows("Name").ToString()) Then
                parentNode.ChildNodes.Add(childNode)
            End If
        Next
    Next
End Sub

Private Function NodeExists(node As TreeNode, key As String) As Boolean
    For Each subNode As TreeNode In node.ChildNodes
        If subNode.Text = key Then
            Return True
        End If
    Next
    Return False
End Function

ScreenShot