Show product count down timer in DataList like Flipkart, Amazon using C# and VB.Net in ASP.Net

Hi eleveth,

Here i have created sample that full-fill your requirement.

HTML

<div>
    <asp:ScriptManager ID="ScriptManager1" runat="server" />
    <asp:UpdatePanel ID="UpdatePanel1" runat="server">
        <ContentTemplate>
            <asp:Timer ID="timer" runat="server" Interval="10">
            </asp:Timer>
            <asp:DataList ID="dlProducts" runat="server" RepeatColumns="4" CellSpacing="3" RepeatLayout="Table"
                OnItemDataBound="dlProducts_ItemDataBound">
                <ItemTemplate>
                    <table>
                        <tr>
                            <td>
                                <asp:HiddenField ID="hfId" runat="server" />
                                <asp:Label ID="lblCatagory" Text='<%# Eval("Catagory")%>' Visible="false" runat="server" />
                                <asp:Label ID="lblDetails" Text='<%# Eval("Details")%>' runat="server" />
                            </td>
                        </tr>
                        <tr>
                            <td>
                                <asp:Image ID="imgImage" ImageUrl='<%# Eval("Image")%>' runat="server" />
                            </td>
                        </tr>
                        <tr>
                            <td>
                                <asp:Label ID="lblPrice" Text='<%# Eval("Price")%>' runat="server" />
                            </td>
                        </tr>
                        <tr>
                            <td>
                                <asp:Label ID="lblTime" runat="server" Font-Bold="true" />
                                <asp:Label ID="lblExpiryTime" Text='<%# Eval("ExpiryDateTime")%>' runat="server"
                                    Visible="false" />
                            </td>
                        </tr>
                    </table>
                </ItemTemplate>
            </asp:DataList>
        </ContentTemplate>
    </asp:UpdatePanel>
</div>

C#

protected void Page_Load(object sender, EventArgs e)
{
    // Get these record from database
    DataTable dt = new DataTable();
    dt.Columns.AddRange(new DataColumn[] { 
        new DataColumn("Id"), new DataColumn("Catagory"), new DataColumn("Details"), 
        new DataColumn("Image"), new DataColumn("Price"), new DataColumn("ExpiryDateTime") });

    dt.Rows.Add(1, "Camera", "Nicon", "~/Images/Chrysanthemum.jpg", "$ 104.04", "2017-06-02 23:00:34");
    dt.Rows.Add(2, "Laptop", "HP 455 14\"", "~/Images/Desert.jpg", "$6.74", "2017-06-02 22:15:34");
    dt.Rows.Add(3, "TV", "Samsung 32\" EH4000G", "~/Images/Hydrangeas.jpg", "$ 39.18", "2017-06-02 22:00:14");
    dt.Rows.Add(4, "Coffee", "Nescafe Piccolo", "~/Images/Jellyfish.jpg", "$ 18.88", "2017-06-02 21:58:58");
    dlProducts.DataSource = dt;
    dlProducts.DataBind();
}

public string CalculateTimeDifference(DateTime startDate, DateTime expiryDate)
{
    int hours = 0;
    int mins = 0;
    int secs = 0;
    string final = string.Empty;
    if (expiryDate > startDate)
    {
        hours = expiryDate.Subtract(startDate).Hours;
        mins = expiryDate.Subtract(startDate).Minutes;
        secs = expiryDate.Subtract(startDate).Seconds;
        final = string.Format("{0}:{1}:{2}", hours.ToString().PadLeft(2, '0'), mins.ToString().PadLeft(2, '0'), secs.ToString().PadLeft(2, '0'));
    }
    return final;
}

protected void dlProducts_ItemDataBound(object sender, DataListItemEventArgs e)
{
    DateTime expiryDateTime = Convert.ToDateTime((e.Item.FindControl("lblExpiryTime") as Label).Text);
    (e.Item.FindControl("lblTime") as Label).Text = CalculateTimeDifference(DateTime.Now, expiryDateTime);
}

VB.Net

Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
    ' Get these record from database
    Dim dt As New DataTable()
    dt.Columns.AddRange(New DataColumn() {New DataColumn("Id"), New DataColumn("Catagory"), New DataColumn("Details"), New DataColumn("Image"), New DataColumn("Price"), New DataColumn("ExpiryDateTime")})

    dt.Rows.Add(1, "Camera", "Nicon", "~/Images/Chrysanthemum.jpg", "$ 104.04", "2017-06-02 23:00:34")
    dt.Rows.Add(2, "Laptop", "HP 455 14""", "~/Images/Desert.jpg", "$6.74", "2017-06-02 22:15:34")
    dt.Rows.Add(3, "TV", "Samsung 32"" EH4000G", "~/Images/Hydrangeas.jpg", "$ 39.18", "2017-06-02 22:00:14")
    dt.Rows.Add(4, "Coffee", "Nescafe Piccolo", "~/Images/Jellyfish.jpg", "$ 18.88", "2017-06-02 21:58:58")
    dlProducts.DataSource = dt
    dlProducts.DataBind()
End Sub

Public Function CalculateTimeDifference(startDate As DateTime, expiryDate As DateTime) As String
    Dim hours As Integer = 0
    Dim mins As Integer = 0
    Dim secs As Integer = 0
    Dim final As String = String.Empty
    If expiryDate > startDate Then
        hours = expiryDate.Subtract(startDate).Hours
        mins = expiryDate.Subtract(startDate).Minutes
        secs = expiryDate.Subtract(startDate).Seconds
        final = String.Format("{0}:{1}:{2}", hours.ToString().PadLeft(2, "0"c), mins.ToString().PadLeft(2, "0"c), secs.ToString().PadLeft(2, "0"c))
    End If
    Return final
End Function

Protected Sub dlProducts_ItemDataBound(sender As Object, e As DataListItemEventArgs)
    Dim expiryDateTime As DateTime = Convert.ToDateTime(TryCast(e.Item.FindControl("lblExpiryTime"), Label).Text)
    TryCast(e.Item.FindControl("lblTime"), Label).Text = CalculateTimeDifference(DateTime.Now, expiryDateTime)
End Sub

Screenshot