Question

dropdownlist二级联动问题，求救

现在的情况是dropdownlist1可以完整地显示7个选项，但不管怎么选择，dropdownlist2死活就是空白，代码如下，请帮我看看怎么改，谢谢

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim sql As String = "select distinct 车型 from 零件信息表"
Dim mycomm As New SqlClient.SqlCommand(sql, myconn)
Dim mydatareader As SqlClient.SqlDataReader
If Not IsPostBack Then
If (myconn.State = ConnectionState.Closed) Then
myconn.Open()
End If
mydatareader = mycomm.ExecuteReader()
Me.Dropdownlist1.DataSource = mydatareader
Me.Dropdownlist1.DataTextField = "车型"
Me.Dropdownlist1.DataBind()
myconn.Close()
End If
End Sub

Private Sub Dropdownlist1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Dropdownlist1.SelectedIndexChanged
Session("cartype") = Dropdownlist1.SelectedValue.ToString
Dim sql1 As String = "select distinct 名称 from 零件信息表 where 车型='" & Session("cartype") & "'"
Dim mycomm1 As New SqlClient.SqlCommand(sql1, myconn)
Dim mydatareader1 As SqlClient.SqlDataReader
If Not IsPostBack Then
If (myconn.State = ConnectionState.Closed) Then
myconn.Open()
End If
mydatareader1 = mycomm1.ExecuteReader()
Me.Dropdownlist2.DataSource = mydatareader1
Me.Dropdownlist2.DataTextField = "名称"
Me.Dropdownlist2.DataBind()
myconn.Close()
End If
End Sub

Answer 1

不好意思,实在是看不下去了.
看的我头晕目眩的,实现你说的数据库操作哪用你这么麻烦的啊.
vb 中有很多的数据库控件的,你要实现的问题几句代码就可以了.
我昨天刚答的别人的,和你的情况差不多.你看着改改吧.
用 datalist控件,很省事.
http://zhidao.baidu.com/question/53779770.html