Hello,
Version 10.1.20101.2013
In the attached sample project, if I update the column "field_int" with an invalid value like "a", then I click inside one of the 2 textbox on the right, I get stuck in a infinite loop of "Data Error" messages.
How to solve this issue ?
Hi,
I'm pretty sure that this is happening because you are parenting forms inside of other forms.It's probably the same issue I reported to Microsoft here:
Showing a MessageBox and setting focus to a control in the Leave event of that control inside nested ContainerControls causes an infinite loop. | Microsoft Connect
I strongly advise you against doing this. In my experience, this will cause all sorts of problems with the tab order and focus issues.
I replaced child forms with user controls and indeed the problem goes away.
Many thanks !
Hi Andreas,
Sorry, but I don't have the sample any more and it looks like the Microsoft Feedback page is no longer available. As far as I can recall, the issue occurs when you have nest ContainerControls and you try to show a MessageBox or other dialog inside the Leave event of a control inside the nested container. So I would think it should be fairly easy to reproduce - assuming Microsoft hasn't already fixed it.
@Mike Saltzman: In our company we have a similar problem with SelectNextControl invoked by our code. I'm very interested in the sample code you've provided Microsoft to prove the error. Is it possible that you email me that sample? Sorry for OT posting here, but it was the only chance for me to contact you.
GreetzAndy Fischer
I don't know how common it is, but I attached a sample project to my report to Microsoft that demonstrates the bug with a couple of ContainerControl-derived controls and no Infragistics controls. It's very clearly a bug in the DotNet Framework.
The problem occurs with 2 levels of nesting. That is, a ContainerControl inside another ContainerControl.
There's nothing inherently bad about using more levels of nested ContainerControls as far as I know. This one bug is the only issue I am aware of.
My advice is to simply avoid ContainerControl nesting. You can next control without having those controls be ContainerControls.
Thank you Mike.
I tried googling but did not find much results about this issue, beside your bug report.
Is this common knowledge in Winforms that nested UserControl/ContainerControl should be avoided ? Do you have any other references stating this ?
How many levels of nesting is considered bad, 3 and more ? It is really not that hard to reach 3 levels in a screen with some tabs...
You are correct that nesting like this will cause the issue. This is the same issue that I reported to Microsoft, and it's a bug in the DotNet framework. Unfortunately, there is nothing we can do about this.
I recommend that if you are going to nest controls, you use a base class for your controls that do not rely on the ContainerControl class. So, for example, instead of using UserControl (which derives from ContainerControl), you could simply derive your controls from the Control class.
This means you won't be able to see your controls in the designer, but it's the only way I know of to avoid the infinite loop of dialogs.
If this is a problem you face often, then what I would do is create two configurations of your application and then use a #if so that your controls derive from UserControl in one configuration which you can use to design them, and then use a separate configuration where your controls derive from Control for release to your users.