AJAX ScriptManager in UserControl

Question

I have a UserControl that contains an UpdatePanel which wraps some other controls. The UserControl will be used on some pages that already have a ScriptManager and other pages that do not have a ScriptManager. I'd like the UserControl to automatically bring its own ScriptManager if one does not exist.

I have tried ScriptManager.GetCurrent and if it returns null i create my own ScriptManager and insert it into the Form but I can't find a place early enough in the UserControl's lifecycle to run this code. I keep getting the error "The control with ID 'uPnlContentList' requires a ScriptManager on the page. The ScriptManager must appear before any controls that need it." every time i try loading the page. The places i've tried running my code are OnInit, CreateChildControls and PageLoad and they never get called because it dies before reaching them.

Where should I put this check?

Peridotite

Answer 1

I hate to come at this in another direction, but are you using a master page? And if so, have you considered placing a single ScriptManager on it and being done with it?

Sixteenmo

No there are no master pages....Don't get me started :) My hands are tied on that decision. – Peridotite

why is this the answer? – Fracas

Answer 2

put a ScriptManager in your MasterPage that all your ASPX files reference. Then anywhere else in the site that you need to work with the ScriptManager use a ScriptManagerProxy that will get the ScriptManager from the master page and let you work with it in the user control and in the code behind.

Now calling ScriptManager.GetCurrent(Page) will give you a reference to a script manager.

<asp:ScriptManagerProxy>
  <Scripts>
    <asp:ScriptReference Path="~/Scripts/myscript.js" />
  <Scripts>
</asp:ScriptManagerProxy>

Here's a link:

MSDN Info

Foxglove

Sorry I don't have an cannot have a masterpage. It's an existing system and we're not allowed to go through and change all of the existing pages...That's why i'm trying to put the smarts in the usercontrol. – Peridotite

what would ~/Scripts/myscript.js contain? – Canard

Answer 3

I think the Init event should work. Use the technique you described (i.e. checking that ScriptManager.GetCurrent returns null before adding) but when you add the ScriptManager, make sure you add it as the first control inside the form.

I haven't tested this but I think it will work.

Quentin

Sorry, as i said, the Init event isn't even hit because an exception is thrown earlier... – Peridotite

Answer 4

What worked for me was including this line after < form >

 <asp:ScriptManager ID="scriptManager" runat="server"/>

That got me around the "...requires a ScriptManager on the page. The ScriptManager must appear before any controls that need it."

Alarum

Answer 5

I have made 2 things that works.

On the UserControl make this Sub:

Public Sub SetFocus()
    txtBox.Focus()
End Sub

On the caling site, call this before your ScriptManagerCall

userControl.SetFocus()

If you have AutoPostback on you UserControl you also have to set the focus in TextChanged event.

Protected Sub txtBox_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles txtBox.TextChanged
    txtBox.Focus()
    ......
End Sub

Hope this works.

Torrent