Access Multiple Dynamic Dropdownlists selected Value - ASP.Net - asp.net

Question

I am adding multiple dynamic dropdownlists to my form.
I'm wanting to access the selected values of the dropdownlists on click of a button.
Private pnlDropDownList As Panel
Protected Sub Page_PreInit(ByVal sender As Object, ByVal e As EventArgs) Handles Me.PreInit
'Create a Dynamic Panel
pnlDropDownList = New Panel()
pnlDropDownList.ID = "pnlDropDownList"
pnlDropDownList.BorderWidth = 1
pnlDropDownList.Width = 300
Me.form1.Controls.Add(pnlDropDownList)
'Create a LinkDynamic Button to Add TextBoxes
Dim btnAddDdl As New Button
btnAddDdl.ID = "btnAddDdl"
btnAddDdl.Text = "Add DropDownList"
AddHandler btnAddDdl.Click, AddressOf btnAdd_Click
Me.form1.Controls.Add(btnAddDdl)
'Recreate Controls
RecreateControls("ddlDynamic", "DropDownList")
End Sub
Protected Sub btnAdd_Click(ByVal sender As Object, ByVal e As EventArgs)
Dim cnt As Integer = FindOccurence("ddlDynamic")
CreateDropDownList("ddlDynamic-" & Convert.ToString(cnt + 1))
End Sub
Private Function FindOccurence(ByVal substr As String) As Integer
Dim reqstr As String = Request.Form.ToString()
Return ((reqstr.Length - reqstr.Replace(substr, "").Length) / substr.Length)
End Function
Private Sub RecreateControls(ByVal ctrlPrefix As String, ByVal ctrlType As String)
Dim ctrls As String() = Request.Form.ToString().Split("&"c)
Dim cnt As Integer = FindOccurence(ctrlPrefix)
If cnt > 0 Then
For k As Integer = 1 To cnt
For i As Integer = 0 To ctrls.Length - 1
If ctrls(i).Contains((ctrlPrefix & "-") + k.ToString()) AndAlso Not ctrls(i).Contains("EVENTTARGET") Then
Dim ctrlID As String = ctrls(i).Split("="c)(0)
If ctrlType = "DropDownList" Then
CreateDropDownList(ctrlID)
End If
Exit For
End If
Next
Next
End If
End Sub
Private Sub CreateDropDownList(ByVal ID As String)
Dim ddl As New DropDownList()
ddl.ID = ID
ddl.DataSource = Me.odsNames
ddl.DataTextField = "Name"
ddl.DataValueField = "ID"
ddl.DataBind()
ddl.Items.Insert(0, New ListItem("All", -1))
ddl.SelectedIndex = 0
ddl.AutoPostBack = True
AddHandler ddl.SelectedIndexChanged, AddressOf OnSelectedIndexChanged
pnlDropDownList.Controls.Add(ddl)
Dim lt As New Literal()
lt.Text = "<br />"
pnlDropDownList.Controls.Add(lt)
End Sub
Protected Sub OnSelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
'Not used, want to get Values from button click
End Sub
Protected Sub cmdAdd_Click(ByVal sender As Object, ByVal e As EventArgs) Handles cmdAdd.Click
Dim cnt As Integer = FindOccurence("ddlDynamic")
pnlDropDownList.Controls.Remove(pnlDropDownList.FindControl("ddlDynamic-" & Convert.ToString(cnt)))
End Sub
This is where I would like to check all dynamic dropdownlists and extract their selected values
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click
'' Check All dynamic Dropdownlists and retrieve selected values
End Sub
End Class
Any assistance would be much appreciated. thanks

Answer 1

You could use Linq to get the references of your dynamic DropDowns in the panel:
Dim allDdls = pnlDropDownList.Controls.OfType(Of DropDownList)()
For Each ddl In allDdls
Dim selectedValue = ddl.SelectedValue
Next