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User controls and their state?

Posted By:      Posted Date: May 22, 2011    Points: 0   Category :ASP.Net

Hi everyone,

I'm new to ASP.NET and have a question about a user/web control's state...

I have usercontrol that contains a listbox with predefined items. I click a button and it adds that item to a dropdownlist. When I change the dropdownlist item, it does a postback (i have autopostback enabled). Each time i add another item to the dropdownlist, it remembers all of its items!

If I add a public property (with a private field to store) of a list, every postback, this list is then empty.

Why are controls treated differently to properties? How do I store the property values if they keep clearing?

Thank you in advance,

Jaclyn (very confused!)

Source code below.

///Code behind
Partial Class uc_WebUserControl
    Inherits System.Web.UI.UserControl

    Public manualList As New Generic.List(Of String)

    Protected Overrides Sub OnLoad(ByVal e As System.EventArgs)

        Label2.Text += "Load"
        For Each i As String In manualList
            Label2.Text += i
        For Each i As ListItem In DropDownList1.Items
            Label2.Text += i.Text
        Label2.Text += "Load"
    End Sub

    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click

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