How to auto update the row based on month or date?

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" DataKeyNames="id" 
OnRowEditing="GridView1_RowEditing" OnRowUpdating="GridView1_RowUpdating">
    <Columns>
        <asp:BoundField DataField="id" HeaderText="S.No." />
        <asp:BoundField DataField="name" HeaderText="Name" />
        <asp:CommandField ShowEditButton="true" />
        <asp:CommandField ShowDeleteButton="true" />
        </Columns>
    </asp:GridView>

protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
        {
            int userid = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Value.ToString());
            GridViewRow row = (GridViewRow)GridView1.Rows[e.RowIndex];
            Label lblID = (Label)row.FindControl("lblID");
            TextBox textName = (TextBox)row.Cells[0].Controls[0];
            GridView1.EditIndex = -1;
            conn.Open();
            SqlCommand cmd = new SqlCommand("update detail set name='"+textName.Text+"' where id='"+userid+"'",conn);
            cmd.ExecuteNonQuery();
            conn.Close();
            FillGrid();
        }


	protected void FillGrid()
        {
            conn.Open();
            SqlCommand cmd = new SqlCommand("Select * from detail", conn);
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            da.Fill(ds);
            conn.Close();
            if (ds.Tables[0].Rows.Count > 0)
            {
                GridView1.DataSource = ds;
                GridView1.DataBind();
            }
            else
            {
                ds.Tables[0].Rows.Add(ds.Tables[0].NewRow());
                GridView1.DataSource = ds;
                GridView1.DataBind();
                int columncount = GridView1.Rows[0].Cells.Count;
                GridView1.Rows[0].Cells.Clear();
                GridView1.Rows[0].Cells.Add(new TableCell());
                GridView1.Rows[0].Cells[0].ColumnSpan = columncount;
                GridView1.Rows[0].Cells[0].Text = "No Records Found";
            }
 
        }      


 protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
        {
            GridView1.EditIndex = e.NewEditIndex;
            FillGrid();
        }