using link buuton clicking in grid view, show the selected row in another grid view., i didnt use any kind of ID here., please... i am in need., please.,

 SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ToString());
    protected void Page_Load(object sender, EventArgs e)
    {
        SqlDataAdapter da = new SqlDataAdapter("select * from BusesInfo", con);
        DataTable dt = new DataTable();
        da.Fill(dt);
        GridView1.DataSource = dt;
        DataBind();

    }
    protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
    {
        string examinationid = GridView1.SelectedValue.ToString();
        SqlDataAdapter da = new SqlDataAdapter("select busName, No,fromtime,totime from Buses where BusNo=" + BusNo, con);
        DataTable dt = new DataTable();
        da.Fill(dt);
        GridView2.DataSource = dt;
        DataBind();
        GridView1.Visible = false;
    }
    protected void GridView2_SelectedIndexChanged(object sender, EventArgs e)
    {
        GridView2.Visible = true;
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        GridView1.Visible = true;
    }
}

<asp:gridview id="GridView1" runat="server" autogenerateselectbutton="True" xmlns:asp="#unknown">
        DataKeyNames="BusNo" 
        onselectedindexchanged="GridView1_SelectedIndexChanged">
    </asp:gridview>
    <br />
    <asp:gridview id="GridView2" runat="server" xmlns:asp="#unknown">
        onselectedindexchanged="GridView2_SelectedIndexChanged">
    </asp:gridview>