THanks for the reply.
THe id is coming for the database not from previous page.

Code:
<asp:repeater id="myview">
<....
>
<tr>
//so i add a hyperlink I can pick up the value from the database using 
<td><asp:hyperlink navigateurl='<%# "nextpage.aspx?folder="+DataBinder.Eval(Container.DataItem, "ID")%>' ........




</td>
</tr>
....
</asp:Repeater>
this opens a new full IE window, i want a popup. If i try as a button and doesn't seem to get it right.

Code:
<asp:repeater id="myview">
<....
>
<tr>
//so i add a hyperlink I can pick up the value from the database using 
<td><asp:button onclick='window.open(<%# "nextpage.aspx?folder="+DataBinder.Eval(Container.DataItem, "ID")%>', height,width)  ........



</td>
</tr>
....
</asp:Repeater>
or try like this
Code:
/or
<td><asp:button onclick="popup">

//c# code in the same aspx page
void popup(object sender, System.EventArgs e){


//how do i get the value from the database here, there is no value attribute to a button
//which i call to differentiate different button that are clicked and where do i add the attribute.

Btn.Attributes.Add("onclick", "window.showModalDialog('target.aspx','', 'dialogHeight: 200px; dialogWidth: 300px;')");

}
Hope i make sense now.