ASP.NET

protected void GridView2_SelectedIndexChanging(object sender, GridViewSelectEventArgs e)<br />
    {//GridViewRow row = GridView2.SelectedRow; <br />
        Response.Write(e.NewSelectedIndex);<br />
    }<br />
    protected void GridView2_SelectedIndexChanged(object sender, EventArgs e)<br />
    {<br />
       TextBox4.Text = GridView2.SelectedRow.Cells[0].Text;<br />
    }<br />

<asp:GridView ID="GridView2" runat="server" OnSelectedIndexChanging="GridView2_SelectedIndexChanging"<br />
OnSelectedIndexChanged="GridView2_SelectedIndexChanged"<br />
  DataKeyNames="NUM_INSCRIPTION"<br />
          OnRowCancelingEdit ="GridView2_RowCancelingEdit" OnRowUpdating ="GridView2_RowUpdating" OnRowEditing="GridView2_RowEditing" AutoGenerateColumns="False"  AllowPaging="True"><br />
    <SelectedRowStyle BackColor="Yellow" /><br />
<Columns><br />
<asp:TemplateField><br />
<EditItemTemplate><br />
<asp:TextBox ID="id0" runat="server" Text='<%# Bind("C1") %>'></asp:TextBox> <br />
</EditItemTemplate><br />
<ItemTemplate><br />
<asp:Label ID="id01" runat="server" Text='<%# Bind("C1") %>'></asp:Label><br />
</ItemTemplate><br />
</asp:TemplateField><br />
<asp:TemplateField><br />
<EditItemTemplate><br />
<asp:TextBox ID="id1" runat="server" Text='<%# Bind("C2 ") %>'></asp:TextBox> <br />
</EditItemTemplate><br />
<ItemTemplate><br />
<asp:Label ID="id11" runat="server" Text='<%# Bind("C2 ") %>'></asp:Label><br />
</ItemTemplate><br />
</asp:TemplateField><br />
<asp:TemplateField><br />
<EditItemTemplate><br />
<asp:TextBox ID="id2" runat="server" Text='<%# Bind("C3 ") %>'></asp:TextBox> <br />
</EditItemTemplate><br />
<ItemTemplate><br />
<asp:Label ID="id21" runat="server" Text='<%# Bind("C3") %>'></asp:Label><br />
</ItemTemplate><br />
</asp:TemplateField><br />
    <asp:CommandField ShowEditButton="True" ShowSelectButton="True" /><br />
</Columns><br />
</asp:GridView><br />

DataTable dt = new DataTable();
            DataRow dr;

            dt.Columns.Add(new DataColumn("userid"));
            dt.Columns.Add(new DataColumn("username"));
            dt.Columns.Add(new DataColumn("city"));

            foreach (GridViewRow gr in GridView1.Rows)
            {
                //if (((CheckBox)(gr.FindControl("chkbx"))).Checked == true)

                if (((CheckBox)gr.Cells[3].FindControl("chkbx")).Checked == true)
                {
                    dr = dt.NewRow();
                    dr["userid"] = gr.Cells[0].Text;
                    dr["username"] = gr.Cells[1].Text;
                    dr["city"] = gr.Cells[2].Text;
                    dt.Rows.Add(dr);
                }
            }
            GridView2.DataSource = dt;
            GridView2.DataBind();