Calculate difference between current and specified year inside ASP.Net GridView using C# and VB.Net

Hi kankon,

Refer below sample.

HTML

<asp:GridView ID="gvDetails" runat="server" AutoGenerateColumns="False" OnRowDataBound="OnRowDataBound">
    <Columns>
        <asp:BoundField DataField="Id" HeaderText="Id" ReadOnly="true" />
        <asp:BoundField DataField="User" HeaderText="User" />
        <asp:TemplateField HeaderText="Age">
            <ItemTemplate>
                <asp:HiddenField ID="hfDOB" runat="server" Value='<%# Eval("DOB") %>' />
                <asp:Label ID="lblAge" runat="server"></asp:Label>
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

Namespaces

C#

using System.Data;

VB.Net

Imports System.Data

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    DataTable dt = new DataTable();
    dt.Columns.AddRange(new DataColumn[3] {
        new DataColumn("Id"),
        new DataColumn("User"),
        new DataColumn("DOB", typeof(DateTime))
    });
    dt.Rows.Add(1, "John Hammond", "2022/05/05");
    dt.Rows.Add(2, "Mudassar Khan", "2004/04/04");
    dt.Rows.Add(3, "Suzanne Mathews", "2005/03/03");
    dt.Rows.Add(4, "Robert Schidner", "2000/02/02");
    gvDetails.DataSource = dt;
    gvDetails.DataBind();
}

protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        DateTime dob = Convert.ToDateTime((e.Row.FindControl("hfDOB") as HiddenField).Value);
        int current = DateTime.Today.Year;
        (e.Row.FindControl("lblAge") as Label).Text = (current - dob.Year).ToString();
    }
}

VB.Net

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
        Dim dt As DataTable = New DataTable()
        dt.Columns.AddRange(New DataColumn(2) {New DataColumn("Id"), New DataColumn("User"), New DataColumn("DOB", GetType(DateTime))})
        dt.Rows.Add(1, "John Hammond", "2022/05/05")
        dt.Rows.Add(2, "Mudassar Khan", "2004/04/04")
        dt.Rows.Add(3, "Suzanne Mathews", "2005/03/03")
        dt.Rows.Add(4, "Robert Schidner", "2000/02/02")
        gvDetails.DataSource = dt
        gvDetails.DataBind()
    End Sub

    Protected Sub OnRowDataBound(ByVal sender As Object, ByVal e As GridViewRowEventArgs)
        If e.Row.RowType = DataControlRowType.DataRow Then
            Dim dob As DateTime = Convert.ToDateTime((TryCast(e.Row.FindControl("hfDOB"), HiddenField)).Value)
            Dim current As Integer = DateTime.Today.Year
            (TryCast(e.Row.FindControl("lblAge"), Label)).Text = (current - dob.Year).ToString()
        End If
    End Sub

Screenshot