Calculate days remaining to birthday using C# and VB.Net in ASP.Net

Hi ashish007,

Check this example. Now please take its reference and correct your code.

Database

For this example I have used of Northwind database that you can download using the link given below.

Download Northwind Database

HTML

<asp:DataList ID="DataList1" runat="server" RepeatColumns="2" HorizontalAlign="Center" RepeatDirection="Horizontal" CellSpacing="3">
    <ItemTemplate>
        <table>
            <tr>
                <td>
                    <asp:HiddenField ID="hfDOB" runat="server" Value='<%#Eval("BirthDate") %>' />
                    <asp:Label runat="server" Text='<%#Eval("FirstName") %>'></asp:Label>
                    <asp:Label runat="server" Text='<%#Eval("LastName") %>'></asp:Label>
                    <br />
                    <br />
                    <asp:Label ID="lblbday" runat="server" Text="Birthday" Font-Bold="true" ForeColor="Green"></asp:Label>
                </td>
            </tr>
        </table>
    </ItemTemplate>
</asp:DataList>

Namespaces

C#

using System.Configuration;
using System.Data;
using System.Data.SqlClient;

VB.Net

Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        this.BindData();
    }
}

private void BindData()
{
    string conString = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    string query = "SELECT * FROM Employees";
    using (SqlConnection con = new SqlConnection(conString))
    {
        SqlCommand cmd = new SqlCommand(query);
        using (SqlDataAdapter sda = new SqlDataAdapter())
        {
            cmd.Connection = con;
            sda.SelectCommand = cmd;
            using (DataTable dt = new DataTable())
            {
                sda.Fill(dt);

                this.DataList1.DataSource = dt;
                this.DataList1.DataBind();
                foreach (DataListItem item in DataList1.Items)
                {
                    Label lblday = item.FindControl("lblbday") as Label;
                    DateTime birthDate = Convert.ToDateTime((item.FindControl("hfDOB") as HiddenField).Value.Trim());
                    lblday.Text = this.ShowBirthDate(birthDate);
                }
            }
        }
    }
}

public string ShowBirthDate(DateTime startDate)
{
    string remain = string.Empty;
    DateTime now = DateTime.Now;
    if (startDate.Month == now.Month)
    {
        int birthDate = startDate.Day;
        int todayDate = now.Day;
        if (birthDate > todayDate)
        {
            remain = "Birth Day come in " + (birthDate - todayDate).ToString() + " days.";
        }
    }

    return remain;
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Me.BindData()
    End If
End Sub

Private Sub BindData()
    Dim conString As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Dim query As String = "SELECT * FROM Employees"
    Using con As SqlConnection = New SqlConnection(conString)
        Dim cmd As SqlCommand = New SqlCommand(query)
        Using sda As SqlDataAdapter = New SqlDataAdapter()
            cmd.Connection = con
            sda.SelectCommand = cmd
            Using dt As DataTable = New DataTable()
                sda.Fill(dt)
                Me.DataList1.DataSource = dt
                Me.DataList1.DataBind()
                For Each item As DataListItem In DataList1.Items
                    Dim lblday As Label = TryCast(item.FindControl("lblbday"), Label)
                    Dim birthDate As DateTime = Convert.ToDateTime((TryCast(item.FindControl("hfDOB"), HiddenField)).Value.Trim())
                    lblday.Text = Me.ShowBirthDate(birthDate)
                Next
            End Using
        End Using
    End Using
End Sub

Public Function ShowBirthDate(ByVal startDate As DateTime) As String
    Dim remain As String = String.Empty
    Dim now As DateTime = DateTime.Now
    If startDate.Month = now.Month Then
        Dim birthDate As Integer = startDate.Day
        Dim todayDate As Integer = now.Day
        If birthDate > todayDate Then
            remain = "Birth Day come in " & (birthDate - todayDate).ToString() & " days."
        End If
    End If

    Return remain
End Function

Screenshot