Question

我正在为学校做一个小网站而且我遇到了这个问题。如何获得每个下拉列表的值？下拉列表由代码动态生成。我对文本框做了同样的工作并且它完美地工作，但是由于下拉列表的值不起作用，我的意思是，我没有得到这些值。我该怎么办？

Partial Class Opties
Inherits System.Web.UI.Page

Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
Dim aantalMensen As Integer = CInt(Session("aantalVolwassenen")) + CInt(Session("aantalKinderen")) + CInt(Session("aantalBabys"))
Session("aantalMensen") = CStr(aantalMensen)

For x As Integer = 1 To aantalMensen
  'Passagiers info
  Dim aanhef As New DropDownList()
  Dim aanhefSelectie As ListItem
  aanhefSelectie = New ListItem("Dhr.", "Dhr.")
  aanhef.Items.Add(aanhefSelectie)
  aanhefSelectie = New ListItem("Mevr.", "Mevr.")
  aanhef.Items.Add(aanhefSelectie)
  Dim voornaam As New TextBox With {.ID = "txtVoornaam" & x}
  Dim achternaam As New TextBox With {.ID = "txtAchternaam" & x}


  Dim lt As New Literal()
  Dim Endlt As New Literal()
  Dim space As New Literal()
  lt.Text = "<p>Persoon " + CStr(x) + ":"
  Endlt.Text = "</p> "
  space.Text = "<br />"

  gegevensPassagiers.Controls.Add(lt)
  gegevensPassagiers.Controls.Add(aanhef)
  gegevensPassagiers.Controls.Add(voornaam)
  gegevensPassagiers.Controls.Add(achternaam)
  gegevensPassagiers.Controls.Add(Endlt)
  gegevensPassagiers.Controls.Add(space)
Next

For i As Integer = 1 To aantalMensen
  'Bagage DropDownlist
  Dim aantalKG As New DropDownList With {.ID = "ddlBagage" & i}
  Dim KGselectie As ListItem
  KGselectie = New ListItem("Geen", "Geen")
  aantalKG.Items.Add(KGselectie)
  KGselectie = New ListItem("15kg", "15kg")
  aantalKG.Items.Add(KGselectie)
  KGselectie = New ListItem("25kg", "25kg")
  aantalKG.Items.Add(KGselectie)
  KGselectie = New ListItem("35kg", "35kg")
  aantalKG.Items.Add(KGselectie)
  aantalKG.AutoPostBack = True

  Dim lt As New Literal()
  Dim Endlt As New Literal()
  Dim space As New Literal()
  lt.Text = "<p>Persoon " + CStr(i) + ":"
  Endlt.Text = "</p> "
  space.Text = "<br />"

  bagageDIV.Controls.Add(lt)
  bagageDIV.Controls.Add(aantalKG)
  bagageDIV.Controls.Add(Endlt)
  bagageDIV.Controls.Add(space)
Next
Dim index As Integer = 1
If IsPostBack Then
  For Each key As String In Request.Form.Keys
    If key.Contains("txtVoornaam") Then
      Session("Voornaam" & index) = CType(Request.Form(key), String)
      index += 1
    End If
    If key.Contains("txtFamilienaam") Then
      Session("Familienaam" & index) = CType(Request.Form(key), String)
      index += 1
    End If
    If key.Contains("ddlBagage") Then
      Session("Bagage" & index) = CType(Request.Form(key), String)
      index += 1
    End If
  Next

End If

End Sub

Answer 1

您可以使用JavaScript获取下拉列表的选定值。例如：

var e = document.getElementById("aanhef ");
var Selectedvalue = e.options[e.selectedIndex].value;

Answer 2

那么，在测试了一些方法和属性以及其他东西之后....我找到了一个简单的解决方案来解决我的问题（也感谢帮助@MaCron）。

以下是代码：

For Each aantalKG As DropDownList In bagageDIV.Controls.OfType(Of DropDownList)()
  Session("Bagage" & index) = aantalKG.SelectedValue
  index += 1
Next

如何获取多个动态生成的下拉列表的值？

2 个答案: