By using this site, you agree to our updated Privacy Policy and our Terms of Use. Manage your Cookies Settings.
446,364 Members | 1,576 Online
Bytes IT Community
+ Ask a Question
Need help? Post your question and get tips & solutions from a community of 446,364 IT Pros & Developers. It's quick & easy.

Usercontrol with ajax update panel causes null reference exception.

P: n/a
If you expose a public property of a usercontrol that accesses an object on
the user control it will give a null reference exception when you wrap that
in an update panel.

Others are having the same problem. Here is a complete example:
http://forums.asp.net/thread/1555836.aspx

Related to this: (But I am not doing dynamic user control creation)
http://www.eightpence.com/null-contr...-aspnet-atlas/

Mar 14 '07 #1
Share this Question
Share on Google+
2 Replies


P: n/a
Hi Wayne,

I cannot seem to reproduce the issue you mentioned on asp.net forum. I've
created following simple WebUserControl and it's working fine on a WebForm:

<%@ Control Language="C#" ClassName="WebUserControl" %>

<script runat="server">

protected void Button1_Click(object sender, EventArgs e)
{
// Label1.Text = DateTime.Now.ToString();
LabelText = DateTime.Now.ToString();
}

public string LabelText
{
get { return Label1.Text; }
set { Label1.Text = value; }
}

</script>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click"
Text="Button" />
</ContentTemplate>
</asp:UpdatePanel>
Please note that I'm not adding a ScriptManager onto the UserControl since
only one ScriptManager instance can exist on a WebForm; therefore the
ScriptManager will always be added to the WebForm.

I've also tried to use a MasterPage and still not able to reproduce it.

Would you please post a complete code listing that could reproduce the
issue? Thanks.
Sincerely,
Walter Wang (wa****@online.microsoft.com, remove 'online.')
Microsoft Online Community Support

==================================================
Get notification to my posts through email? Please refer to
http://msdn.microsoft.com/subscripti...ult.aspx#notif
ications. If you are using Outlook Express, please make sure you clear the
check box "Tools/Options/Read: Get 300 headers at a time" to see your reply
promptly.

Note: The MSDN Managed Newsgroup support offering is for non-urgent issues
where an initial response from the community or a Microsoft Support
Engineer within 1 business day is acceptable. Please note that each follow
up response may take approximately 2 business days as the support
professional working with you may need further investigation to reach the
most efficient resolution. The offering is not appropriate for situations
that require urgent, real-time or phone-based interactions or complex
project analysis and dump analysis issues. Issues of this nature are best
handled working with a dedicated Microsoft Support Engineer by contacting
Microsoft Customer Support Services (CSS) at
http://msdn.microsoft.com/subscripti...t/default.aspx.
==================================================

This posting is provided "AS IS" with no warranties, and confers no rights.

Mar 14 '07 #2

P: n/a
Hi Wayne,

Since a web page can contain only one ScriptManager control (either
directly on the page itself or indirectly inside a nested or parent
component), you can use ScriptManagerProxy
(http://ajax.asp.net/docs/mref/T_Syst...agerProxy.aspx)
when you're using UpdatePanel on a content page or a web user control.
Regards,
Walter Wang (wa****@online.microsoft.com, remove 'online.')
Microsoft Online Community Support

==================================================
When responding to posts, please "Reply to Group" via your newsreader so
that others may learn and benefit from your issue.
==================================================

This posting is provided "AS IS" with no warranties, and confers no rights.

Mar 16 '07 #3

This discussion thread is closed

Replies have been disabled for this discussion.