Reset counter after every nth row of ASP.Net GridView using C#

Hi alhamd,

Refer below code.

HTML

<asp:ScriptManager runat="server" />
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
    <ContentTemplate>
        <asp:Label ID="lblMessage" runat="server" />
        <br /><br />
        <asp:GridView ID="GridView1" runat="server"></asp:GridView>
        <asp:Timer ID="Timer1" runat="server" OnTick="TimerTick1" Interval="1000" />
        <asp:HiddenField ID="hfIndex" runat="server" Value="0" />
    </ContentTemplate>
</asp:UpdatePanel>

Code

protected void TimerTick1(object sender, EventArgs e)
{
    BindData();
    if (Convert.ToInt32(hfIndex.Value) % 3 < 3)
    {
        lblMessage.Text = "Coun: A-" + ((int.Parse(hfIndex.Value) % 3) + 1);
    }
    hfIndex.Value = (Convert.ToInt32(hfIndex.Value) + 1).ToString();
}

private void BindData()
{
    DataTable dt = GetData();
    DataTable dtFinal = dt.Clone();
    if (Convert.ToInt32(hfIndex.Value) >= dt.Rows.Count)
    {
        hfIndex.Value = "0";
    }
    dtFinal.Rows.Add(dt.Rows[Convert.ToInt32(hfIndex.Value)].ItemArray);
    GridView1.DataSource = dtFinal;
    GridView1.DataBind();
}

private DataTable GetData()
{
    DataTable dt = new DataTable();
    dt.Columns.Add("Code");
    dt.Columns.Add("Name");
    dt.Rows.Add(1, "A");
    dt.Rows.Add(2, "B");
    dt.Rows.Add(3, "C");
    dt.Rows.Add(4, "D");
    dt.Rows.Add(5, "E");
    dt.Rows.Add(6, "F");
    dt.Rows.Add(7, "G");
    dt.Rows.Add(8, "H");
    dt.Rows.Add(9, "I");
    dt.Rows.Add(10, "J");
    dt.Rows.Add(11, "K");

    return dt;
}

Screenshot