Asp.net DataTable To GridView

<asp:GridView ID="GridView1" runat="server" AllowPaging="True" Height="171px"
            onpageindexchanging="GridView1_PageIndexChanging"
            onrowdatabound="GridView1_RowDataBound"  PageSize="2"
            Width="411px">
            <RowStyle HorizontalAlign="Center" VerticalAlign="Middle" />
            <PagerStyle HorizontalAlign="Center" VerticalAlign="Middle" />
            <HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" />
  </asp:GridView>

 protected void Page_Load(object sender, EventArgs e)
    {
        if(!IsPostBack)
        {
            bindtoGridView();
        }
     
    }
    public void bindtoGridView()
    {
        DataTable dt = new DataTable();
        dt.Columns.Add("id", typeof(int));
        dt.Columns.Add("name");
        dt.Columns.Add("age", typeof(int));
        dt.Columns.Add("phone");
        dt.Rows.Add(1, "老张", 40, "99213812");
        dt.Rows.Add(2, "小李", 28, "a21313");
        dt.Rows.Add(3, "小王", 22, "2131434");
        GridView1.DataSource = dt;
        GridView1.DataKeyNames = new string[] { "id" };
        GridView1.DataBind();
    }
   

    protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
       // e.Row.Cells[0].Visible = false;
    }
    protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
    {
        this.GridView1.PageIndex = e.NewPageIndex;
        bindtoGridView();
    }