refer this simple example
c#
protected void Page_Load(object sender, EventArgs e)
{
if (Page.IsPostBack) return;
GridView1.DataSource = new int[]{1,2,3,4};
GridView1.DataBind();
}
Javascript
function ShowHidTextBox(obj)
{
var value = $('input[type="radio"]:checked', obj).val();
var $textbox = $(obj.parentElement.parentElement).find("[id*='txtcommnet']");
if (value == 'Yes')
$textbox.hide();
else
$textbox.show();
}
<asp:GridView runat="server" ID="GridView1">
<Columns>
<asp:TemplateField>
<ItemTemplate>
<asp:RadioButtonList ID="RadioButtonList1" onchange="ShowHidTextBox(this)" runat="server">
<asp:ListItem Text="Yes" />
<asp:ListItem Text="No" />
</asp:RadioButtonList>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField>
<ItemTemplate>
<asp:TextBox runat="server" ID="txtcommnet" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>