Fire DropDownList event in a repeater *RESOLVED*

[dj4uk]

I have two dropdownlists within a repeater (simplified code below):

<asp:Repeater id="rptProducts" Runat="Server">
	<ItemTemplate>
		<asp:DropDownList id="ddlColour" Runat="Server" DataSource="<%# BindColour((int)DataBinder.Eval(Container.DataItem, "ProductID")) %>" DataTextField="ColourName" DataValueField="ColourID" />
		<asp:DropDownList id="ddlSize" Runat="Server" DataSource="<%# BindSize((int)DataBinder.Eval(Container.DataItem, "ProductID")) %>" DataTextField="SizeName" DataValueField="SizeID" />
	</ItemTemplate>
</asp:Repeater>

The repeater is bound to a list of products. The BindColour and BindSize methods return lists according to the productID for that Item.

My query is how can I detect that the first dropdownlist (colour) has changed value and therefore databind the second dropdownlist again to reflect the selected value.

Basically the first list contains all colours for a particular product and the second dropdown displays sizes for a product AND colour.

Help would be appreciated.

DJ