Hi ishi_12987,

Refer below code.

HTML

<form id="form1" runat="server">
    <div class="navbar navbar-default">
        <div class="container-fluid">
            <div class="navbar-header">
                <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1"
                    aria-expanded="false">
                    <span class="sr-only">Toggle navigation</span> <span class="icon-bar"></span><span
                        class="icon-bar"></span><span class="icon-bar"></span>
                </button>
                <a class="navbar-brand" href="#">ASPSnippets</a>
            </div>
            <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
                <asp:Menu ID="Menu1" runat="server" Orientation="Horizontal" RenderingMode="List"
                    IncludeStyleBlock="false" StaticMenuStyle-CssClass="nav navbar-nav" DynamicMenuStyle-CssClass="dropdown-menu">
                </asp:Menu>
            </div>
        </div>
    </div>
    <script type="text/javascript">
        Sys.WebForms.Menu._elementObjectMapper.getMappedObject = function () {
            return false;
        };
        $(function () {
            $(".navbar-nav li, .navbar-nav a, .navbar-nav ul").removeAttr('style');
            $(".dropdown-menu").closest("li").removeClass().addClass("dropdown-toggle");
            $(".dropdown-toggle").find("a[href='javascript:;']").attr("data-toggle", "dropdown");
            $(".dropdown-toggle").find("a[href='javascript:;'].level1").append("<span class='caret'></span>");
            $(".dropdown-toggle").find("a[href='javascript:;']:not(.level1)").closest('li').addClass('dropdown-submenu');
            $("a.selected").closest("li").addClass("active");
            $("a.selected").closest(".dropdown-toggle").addClass("active");
            $('ul.dropdown-menu [data-toggle=dropdown]').on('click', function (event) {
                event.preventDefault();
                event.stopPropagation();
                $(this).parent().siblings().removeClass('open');
                $(this).parent().toggleClass('open');
            });
        });
    </script>
    <hr />
    <asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server">
    </asp:ContentPlaceHolder>
</form>

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = this.GetData(0);
        PopulateMenu(dt, 0, null);
    }
}

private DataTable GetData(int parentMenuId)
{
    DataTable dt = new DataTable();
    dt.Columns.AddRange(new DataColumn[4] {
    new DataColumn("ParentMenuId"),
    new DataColumn("MenuId"),
    new DataColumn("Title"),
    new DataColumn("Url") });
    dt.Rows.Add(0, 1, "Home", "~/Home.aspx");
    dt.Rows.Add(0, 2, "Master", "javascript:;");
    dt.Rows.Add(0, 3, "Transaction", "javascript:;");
    dt.Rows.Add(0, 4, "Reports", "javascript:;");

    dt.Rows.Add(2, 5, "Common", "javascript:;");

    dt.Rows.Add(3, 6, "Common", "javascript:;");
    dt.Rows.Add(3, 7, "Menu2", "javascript:;");
    dt.Rows.Add(3, 8, "Menu10", "javascript:;");

    dt.Rows.Add(4, 9, "Common1", "javascript:;");
    dt.Rows.Add(4, 10, "Common2", "javascript:;");

    dt.Rows.Add(5, 11, "County", "~/CountryMaster.aspx");
    dt.Rows.Add(5, 12, "City", "~/CityMaster.aspx");
    dt.Rows.Add(5, 13, "State", "~/StateMaster.aspx");

    dt.Rows.Add(6, 14, "Form1", "~/Form1.aspx");
    dt.Rows.Add(6, 15, "Form2", "~/Form2.aspx");

    dt.Rows.Add(7, 16, "Form3", "~/Form3.aspx");
    dt.Rows.Add(7, 17, "Form4", "~/Form4.aspx");

    dt.Rows.Add(8, 18, "Form10", "~/Form10.aspx");

    dt.Rows.Add(9, 19, "Report1", "~/Report4.aspx");
    dt.Rows.Add(9, 20, "Report2", "~/Report2.aspx");
    DataTable dtFinal = dt.Clone();
    DataRow[] dr = dt.Select("ParentMenuId=" + parentMenuId);
    if (dr.Length > 0)
    {
        dtFinal = dr.CopyToDataTable();
    }

    return dtFinal;
}

private void PopulateMenu(DataTable dt, int parentMenuId, MenuItem parentMenuItem)
{
    string currentPage = Path.GetFileName(Request.Url.AbsolutePath);
    foreach (DataRow row in dt.Rows)
    {
        MenuItem menuItem = new MenuItem
        {
            Value = row["MenuId"].ToString(),
            Text = row["Title"].ToString(),
            NavigateUrl = row["Url"].ToString(),
            Selected = row["Url"].ToString().EndsWith(currentPage, StringComparison.CurrentCultureIgnoreCase)
        };
        if (parentMenuId == 0)
        {
            Menu1.Items.Add(menuItem);
            DataTable dtChild = this.GetData(int.Parse(menuItem.Value));
            PopulateMenu(dtChild, int.Parse(menuItem.Value), menuItem);
        }
        else
        {
            parentMenuItem.ChildItems.Add(menuItem);
            if (parentMenuId > 0)
            {
                DataTable dtChild = this.GetData(int.Parse(menuItem.Value));
                PopulateMenu(dtChild, int.Parse(menuItem.Value), menuItem);
            }
        }
    }
}

VB.Net

Protected Sub Page_Load(sender As Object, e As EventArgs)
    If Not Me.IsPostBack Then
        Dim dt As DataTable = Me.GetData(0)
        PopulateMenu(dt, 0, Nothing)
    End If
End Sub

Private Function GetData(parentMenuId As Integer) As DataTable
    Dim dt As DataTable = New DataTable()
    dt.Columns.AddRange(New DataColumn(3) {
                        New DataColumn("ParentMenuId"),
                        New DataColumn("MenuId"),
                        New DataColumn("Title"),
                        New DataColumn("Url")})
    dt.Rows.Add(0, 1, "Home", "~/Home.aspx")
    dt.Rows.Add(0, 2, "Master", "javascript:;")
    dt.Rows.Add(0, 3, "Transaction", "javascript:;")
    dt.Rows.Add(0, 4, "Reports", "javascript:;")

    dt.Rows.Add(2, 5, "Common", "javascript:;")

    dt.Rows.Add(3, 6, "Common", "javascript:;")
    dt.Rows.Add(3, 7, "Menu2", "javascript:;")
    dt.Rows.Add(3, 8, "Menu10", "javascript:;")

    dt.Rows.Add(4, 9, "Common1", "javascript:;")
    dt.Rows.Add(4, 10, "Common2", "javascript:;")

    dt.Rows.Add(5, 11, "County", "~/CountryMaster.aspx")
    dt.Rows.Add(5, 12, "City", "~/CityMaster.aspx")
    dt.Rows.Add(5, 13, "State", "~/StateMaster.aspx")

    dt.Rows.Add(6, 14, "Form1", "~/Form1.aspx")
    dt.Rows.Add(6, 15, "Form2", "~/Form2.aspx")

    dt.Rows.Add(7, 16, "Form3", "~/Form3.aspx")
    dt.Rows.Add(7, 17, "Form4", "~/Form4.aspx")

    dt.Rows.Add(8, 18, "Form10", "~/Form10.aspx")

    dt.Rows.Add(9, 19, "Report1", "~/Report4.aspx")
    dt.Rows.Add(9, 20, "Report2", "~/Report2.aspx")
    Dim dtFinal As DataTable = dt.Clone()
    Dim dr As DataRow() = dt.Select("ParentMenuId=" & parentMenuId)

    If dr.Length > 0 Then
        dtFinal = dr.CopyToDataTable()
    End If

    Return dtFinal
End Function

Private Sub PopulateMenu(dt As DataTable, parentMenuId As Integer, parentMenuItem As MenuItem)
    Dim currentPage As String = Path.GetFileName(Request.Url.AbsolutePath)
    For Each row As DataRow In dt.Rows
        Dim menuItem As New MenuItem() With { _
            .Value = row("MenuId").ToString(), _
            .Text = row("Title").ToString(), _
            .NavigateUrl = row("Url").ToString(), _
            .Selected = row("Url").ToString().EndsWith(currentPage, StringComparison.CurrentCultureIgnoreCase) _
        }
        If parentMenuId = 0 Then
            Menu1.Items.Add(menuItem)
            Dim dtChild As DataTable = Me.GetData(Integer.Parse(menuItem.Value))
            PopulateMenu(dtChild, Integer.Parse(menuItem.Value), menuItem)
        Else
            parentMenuItem.ChildItems.Add(menuItem)
            If parentMenuId > 0 Then
                Dim dtChild As DataTable = Me.GetData(Integer.Parse(menuItem.Value))
                PopulateMenu(dtChild, Integer.Parse(menuItem.Value), menuItem)
            End If
        End If
    Next
End Sub

Screenshot