<asp:GridView ID="gdview"  runat="server" ShowFooter="true" AutoGenerateColumns="False"  DataKeyNames="CategoryID"    >
        <Columns>
            <asp:BoundField HeaderText="Category Name" DataField="CategoryName" SortExpression="CategoryName" >
                <ItemStyle Height="20px" Width="150px" />
            </asp:BoundField>
            <asp:TemplateField>
            <ItemTemplate>
            <asp:Calendar ID="id1" runat="server"  OnSelectionChanged="id1_SelectionChanged"></asp:Calendar>
 
            </ItemTemplate>
 
            </asp:TemplateField>
 
                   </Columns>
 
 
 </asp:GridView>
 
in code behind:
 
 protected void Page_Load(object sender, EventArgs e)
    {
 
        if (!Page.IsPostBack)
        {
            bindgrid();
 
 
        }
 
    }
 
    public void bindgrid()
    {
        SqlConnection conn = new SqlConnection("Data Source='localhost';Initial Catalog='Northwind';Integrated Security=SSPI;Persist Security Info=False ");
        SqlCommand cmd = new SqlCommand("select CategoryName,CategoryID from Categories ", conn);
 
        SqlDataAdapter da = new SqlDataAdapter("", conn);
        da.SelectCommand = new SqlCommand("select CategoryName,CategoryID from Categories", conn);
        DataSet ds = new DataSet();
        da.Fill(ds, "data");
        gdview.DataSource = ds.Tables[0].DefaultView;
        gdview.DataBind();
 
 
    }
    protected void id1_SelectionChanged(object sender, EventArgs e)
    {
        Calendar cal = new Calendar();
        GridViewRow dgrow = (GridViewRow)cal.NamingContainer;
 
    }