SelectedIndex Change Event for DropDownList Inside GridView

[baburk]

I am having dropdownlist inside gridview.

When the dropdownlist selectedindex change an event should fire.

What is the event for his.

I also want to get the dropdownlist event fired row number

<asp:GridView ID = "gvMaterials" runat = "server" AutoGenerateColumns = "false">
<Columns>
<asp:TemplateField HeaderText="MaterialType">
<ItemTemplate >
<asp:DropDownList ID = "ddlMaterialType" runat = "server" Width = "165px" OnSelectedIndexChanged="ddlMaterialType_SelectedIn dexChanged" ></asp:DropDownList>
</ItemTemplate>
</asp:TemplateField>

<asp:TemplateField HeaderText="MaterialName">
<ItemTemplate >
<asp:DropDownList ID = "ddlMaterialName" runat = "server" Width = "165px" ></asp:DropDownList>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>

Thanks