我这样使用是好使的：

(1)string [] m_aryStr = new string [] {"abc", "def", "ghi", "jki"} ;
(2)Draw a datalist1 on a Web form and set datalist1.datasource = m_aryStr ;
(3)Drag dropdownlist1 into datalist1(when designing the template) and right click dropdownlist1 to get the property dialog. set the databinding property of dropdownlist1 , make "datasource" the bindable property and bind container.dataitem to datasource.

(4)end the design of template

(5) call databind() in page_load().

(6) ok now

Public Class myDropDownList
Inherits Control
Implements INamingContainer

Protected Overrides Sub CreateChildControls()

Dim DropDownList1 As New System.Web.UI.WebControls.DropDownList
DropDownList1.DataSource =
DropDownList1.DataMember =
DropDownList1.DataValueField =

DropDownList1.DataBind()

Me.Controls.Add(DropDownList1)

End Sub

End Class

用这个代替DropDownList应该能行. 如果不同DataList's ITEM中的DropDownList用不同数据绑定, 也可以做到