I have a server control that I am trying to get to save properties as control states but for some reason the properties are not persisting across partial postbacks.
The psuedo code is as follows:
Public Class FileUpload
Inherits ScriptControl
Implements INamingContainer, IPostBackEventHandler
Public Property newFileExt() As String
Get
Dim foundList As String = DirectCast(ViewState(Me.UniqueID & "_fileExt"), String)
If foundList IsNot Nothing Then
Return foundList
Else
Return String.Empty
End If
End Get
Set(ByVal value As String)
ViewState(Me.UniqueID & "_fileExt") = value
End Set
End Property
Protected Overrides Sub OnInit(ByVal e As System.EventArgs)
MyBase.OnInit(e)
Page.RegisterRequiresControlState(Me)
End Sub
Protected Overrides Function SaveControlState() As Object
Dim controlState(6) As Object
controlState(0) = MyBase.SaveControlState()
controlState(1) = newFileExt
Return controlState
End Function
Protected Overrides Sub LoadControlState(ByVal savedState As Object)
Dim controlState() As Object
controlState = CType(savedState, Object)
MyBase.LoadControlState(controlState(0))
newFileExt = CType(controlState(1), String)
End Sub
end class
On this control is an asyncFileUpload ajaxcontroltoolkit control and a button. I have an event for upload complete:
Protected Sub SaveUploadedFile(ByVal sender As Object, ByVal e As AjaxControlToolkit.AsyncFileUploadEventArgs) Handles asyncFileUpload.UploadedComplete
newFileExt= "Some Value"
end sub
Protected Sub bntSelectResults_click(ByVal sender As Object, ByVal e As EventArgs) Handles bntSelectResults.Click
If (newFileExt= "") Then
'this always returns as empty
End If
end sub
So, UploadedComplete is complete it should set the controls state. then, when the user click the button it should read it. Through debugging, I can see that it is set correctly in UploadedComplete event but null when read. Is this due to the cycle of the page or something?
Thanks jason
EDIT
I traced out the path for how the page cycle is running:
User clicks the async file upload control's browse button and selects a file. This causes the upload process to start
a. OnInit gets called
b. LoadControlState gets called
c. OnLoad gets called
d. asyncFileUpload.UploadedComplete gets called and I set the newFileExt property here.
e. SaveControlState gets called. newFileExt is set here properly
User clicks a button on the control that initiates another partial postback/update of the update panel a. OnInit gets called
b. LoadControlState gets called. I can see that the newFileExt property is not set
c. OnLoad gets called
d. Buttons click event gets called and the property is read (which is no longer set)
e. SaveControlState gets called and cycle ends
