[Solved] Dynamic loading of UserControls

[Martin]

Hi

I have a question about dynamic loading of controls...
I've got my application working fine using your example
at www.telerik.com/help/aspnet/ajax/ajxloadusercontrols.html

On loading, all my dynamic controls run initialisation code
which typically loads data into the controls UI from a dataset.

Using the example code below:

After the initial page is loaded, I then click on Button2
and the sequence of events is ....

1) ControlONE.ascx is first re-loaded in the "Page Load event".
    - LoadUserControl(LatestLoadedControlName)

2) ControlTWO.ascx is then loaded inside the navigation button "event" and ControlONE.ascx is removed.
    - LoadUserControl("ControlTWO.ascx")

It seems wasteful to re-create the previous control and run initialise code again...

Is this just the way it has to be done ?
I assume because this is happening on the server side then the re-loading of the original
control has no performance effect on the client side?

Regards

Martin Hoey


    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If Not (LatestLoadedControlName Is Nothing) Then
            LoadUserControl(LatestLoadedControlName)
        Else
            LoadUserControl("ControlONE.ascx")
        End If
    End Sub

    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        LoadUserControl("ControlONE.ascx")
    End Sub

    Protected Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button2.Click
        LoadUserControl("ControlTWO.ascx")
    End Sub

    Public Sub LoadUserControl(ByVal controlName As String)
        If Not (LatestLoadedControlName Is Nothing) Then
            Dim previousControl As Control = Panel1.FindControl(LatestLoadedControlName.Split("."c)(0))
            If Not (previousControl Is Nothing) Then
                Me.Panel1.Controls.Remove(previousControl)
            End If
        End If
        Dim userControlID As String = controlName.Split("."c)(0)
        Dim targetControl As Control = Panel1.FindControl(userControlID)
        If targetControl Is Nothing Then
            Dim userControl As UserControl = CType(Me.LoadControl(controlName), UserControl)
            'slashes and tildes are forbidden
            userControl.ID = userControlID.Replace("/", "").Replace("~", "")
            Me.Panel1.Controls.Add(userControl)
            LatestLoadedControlName = controlName
        End If
    End Sub 'LoadUserControl

    Private Property LatestLoadedControlName() As String
        Get
            Return CStr(ViewState("LatestLoadedControlName"))
        End Get
        Set(ByVal value As String)
            ViewState("LatestLoadedControlName") = value
        End Set
    End Property

[Martin]

Hi

I think I understand now....

If I remove :
LoadUserControl(LatestLoadedControlName)
then I eventually get an error "Failed to load viewstate"

Any further clarification appreciated but in the meantime I'm happy (if confused!)
to close this issue...

Regards

Martin