how to access programmatically Imagebutton control?

[Chris]

Hi,

i want to access programmatically the ImageButton1 control in order to
define the postBackUrl in function of other parameters.
I tried: datalist1.findControl("ImageButton1") ...

<asp:datalist id="DataList1" runat="server" datasourceid="SqlDataSource1" >
<ItemTemplate>
<asp:ImageButton id="ImageButton1" runat="server"
PostBackUrl="" ></asp:ImageButton>
</ItemTemplate>
</asp:datalist>

Thanks for help
Chris