I've looked into this quite extensively and I've found the following:
You can do some clever stuff to catch most errors by implementing a base class, see Andreas Knudsen's solution for this.
The Error event in UserControl never gets fired, see details here: http://weblogs.asp.net/vga/archive/2003/06/16/8748.aspx
What I can't find is any general way to catch errors occurring in postback events, such as the click event for a button, at the web part or user control level. What I mean by general is a something I can implement in a baseclass.
I'm aware the I should do proper try/catch in my code, but for large teams I'd like to be sure that a web part never crashes the page, but always shows a nice message and allows execution to continue for the other web parts on the page.
I don't think it's possible but I'd love to be proved wrong.
Thanks,
Bjoern
I think this is possible, but you have to work around the fact that when asp.net distributes the postback events it couldn't care less about your user control definitions, instead it only cares about controls that explicitly implement IPostBackEventHandler (like button / dropdown etc)
For pages you can override and try/catch RaisedPostBackEvent like for the other methods. (if you ever wanted a generic page-exception handling setup. (if you want this then please reconsider. I spent way too much time in my last project basically reimplementing the default asp.net exception handling logic just to get this to work. the devil's in the details)
What you could do is to have a base page in your system which all pages inherit from and which overrides RaisePostBackEvent(source, eventArgs). In this method you could see if the source inherits from your exception handling base control, or if it is contained within a control which does this. (navigate the parent graph)
If it is contained by one then do a try/catch around the call to base.Raise.... (see the code in
Transparent generic exception handling for asp.net / MOSS2007 (with code) ) and call the exceptionhappened method on the first candidate you found if indeed any exceptions occur.
Related
I am trying to call a button in the more actions tab of an application from my automation script. Does anyone know what method to call to achieve this?
If it is possible to do what you ask, this answer to another question will get you heading in the right direction. You'll need to know the name of the event / method to call, and you may find psdi.webclient.system.beans.DataBean.findAndCallMethod() useful.
But it is often the case that the event / method behind such buttons just calls on other server-side logic. So, you might be working harder rather than smarter by trying to do this. It might be smarter to look in the Maximo JavaDocs for the class on the object you're working with for a method that sounds like what you want to do. Or look on the service the database object is in. (You can find the classes for the objects and services in Database Configuration.)
If someone knows better, I'm happy to hear from them.
This is not a technical question, but rather an inquiry on how to get better information regarding the huge numbr of parameters and properties of the various controls you can put in an XPage.
A concrete example:
I have a button which had a property save=true in its event Handler. I added some code in the postSave event, so a lotuscript angent could do some processing, and I started having save conflicts. It took a while but I managed to figure out that the save=true in the event Handler was causing the issue.
I like to know my options, so I wanted to look at what exactly that property ws doing (although the name kinds of give it), but that's when it hit me: where do I look for that kind of information?
Is there a site somewhere that lists all properties we can add and a description of what they are doing?
Maybe my Google skills are not the best, but I couldn't find anything yet...
The three IBM Press XPages books (Mastering XPages 2nd Edition, XPages Portable Command Guide and XPages Extension Library) are key to understanding the implications of the properties. There are the equivalent of Javadocs for controls (here's the link for the XPages Extension Library one), but they're not intended to go into the kind of depth to identify the problem you hit.
These might be useful:
http://xpageswiki.com/
http://www-01.ibm.com/support/knowledgecenter/SSVRGU_9.0.1/com.ibm.designer.domino.ui.doc/wpd_controls_cref.html
Howard
Background
I'm going to develop a new web-application with java. It's not very big or very complex and I have enough time until it'll "officially" start.
I have some JSF/Facelets development background (about half a year). And I also have some expirience with JSP+JSTL.
In self-educational purpose (and also in order to find the best solution) I want to prototype the new project with one of action-based frameworks. Actually, I will choose between Spring MVC and Stripes.
Problem
In order to get correct impression about action-based frameworks (in comparison with JSF) I want to be sure that I use them correctly (in a bigger or a lesser extent).
So, here I list some most-frequent tasks (at least for me) and describe how I solve them with JSF. I want to know how they should be solved with action-based framework (or separately with Spring MVC and Stripes if there is any difference for concrete task).
Rendering content: I can apply ready-to-use component from standard jsf libraries (core and html) or from 3rd-party libs (like RichFaces). I can combine simple components and I can easily create my own components which are based on standard components.
Rendering data (primitive or reference types) in the correct format: Each component allow to specify a converter for transforming data in both ways (to render and to send to the server). Converter is, as usual, a simple class with 2 small methods.
Site navigation: I specify a set of navigation-cases in faces-config.xml. Then I specify action-attribute of a link (or a button) which should match one or more of navigation cases. The best match is choosen by JSF.
Implementing flow (multiform wizards for example): I'm using JSF 1.2 so I use Apache Orchestra for the flow (conversation) scope.
Form processing: I have a pretty standard java-bean (backing bean in JSF terms) with some scope. I 'map' form fields on this bean properties. If everything goes well (no exceptions and validation is passed) then all these properties are set with values from the form fields. Then I can call one method (specified in button's action attribute) to execute some logic and return string which should much one of my navigation cases to go to the next screen.
Forms validation: I can create custom validator (or choose from existing) and add it to almost each component. 3rd-party libraries have sets of custom ajax-validators. Standard validators work only after page is submitted. Actually, I don't like how validation in JSF works. Too much magic there. Many standard components (or maybe all of them) have predefined validation and it's impossible to disable it (Maybe not always, but I met many problems with it).
Ajax support: many 3rd-party libraries (MyFaces, IceFaces, OpenFaces, AnotherPrefixFaces...) have strong ajax support and it works pretty well. Until you meet a problem. Too much magic there as well. It's very difficult to make it work if it doesn't work but you've done right as it's described in the manual.
User-friendly URLs: people say that there are some libraries for that exist. And it can be done with filters as well. But I've never tried. It seems too complex for the first look.
Thanks in advance for explaning how these items (or some of them) can be done with action-based framework.
I'll do my best to answer regarding Stripes. I've used Struts and JSF in the past, but not recently, so at best I have vague notions and feelings about them.
We are intimately familiar w/ Stripes, use it for most everything now, and really enjoy it. It is easy to jump into, supports many of the complicated scenarios, but you are also free to work OUTSIDE of it, which is really important when you want to build your own ajax widgets or talk to another system or something.
If you go the stripes route, I definitely recommend buying or download the book. It is a one stop shop for everything you need for Stripes, and is practically the only documentation for Stripersist (really nice feature, but NO web docs).
Rendering content: I can apply ready-to-use component from standard jsf libraries (core and html) or from 3rd-party libs (like RichFaces). I can combine simple components and I can easily create my own components which are based on standard components.
This is similar. Core, Html, Fmt, etc. as well as any custom tags you find, inc. display:tag, pack tag, and create your own. However, obviously you do not deal at the component level now, you deal with a tag that determines what is on the page / sent to or from the server.
Rendering data (primitive or reference types) in the correct format: Each component allow to specify a converter for transforming data in both ways (to render and to send to the server). Converter is, as usual, a simple class with 2 small methods.
Stripes has many built in converters, and it is easy to create custom converters for your more complex data types. Stripes supports very complex data structures to be mapped with little hassle. Combined with Stripersist, for example, I can put my model object directly on the ActionBean, put a few of the fields on the form, and Stripersist will hydrate the model from the db (based on its PK) and update that with the fields I put on the form - all before releasing control to me on the ActionBean.
Site navigation: I specify a set of navigation-cases in faces-config.xml. Then I specify action-attribute of a link (or a button) which should match one or more of navigation cases. The best match is choosen by JSF.
Navigation in stripes is based on what you name the ActionBeans, initially. There is no xml. Additionally, pretty urls are an annotation at the ActionBean level in Stripes 1.5, so you can do things like #UrlBinding("/{$event}/{model}") where /view/5 would take you to the "view" event handler for your Model object with the ID/PK of 5.
Implementing flow (multiform wizards for example): I'm using JSF 1.2 so I use Apache Orchestra for the flow (conversation) scope.
While I only am vaguely familiar with the concept of conversation scope, Stripes has Wizard Form functionality, but I haven't used it and am unable to really expand on that. I think it is a similar idea though.
Form processing: I have a pretty standard java-bean (backing bean in JSF terms) with some scope. I 'map' form fields on this bean properties. If everything goes well (no exceptions and validation is passed) then all these properties are set with values from the form fields. Then I can call one method (specified in button's action attribute) to execute some logic and return string which should much one of my navigation cases to go to the next screen.
Not drastically different. Instead of components on your [action] bean, you now have Java or custom types. ActionBeans are created per request and thrown away, unless you do something like put it in session, or wizard, or whatever. This is nice, because all the instance variables get mapped to the data from the form, you use it, then throw it away, and don't have to deal with any synchronization issues like struts did. After you do your thing with the data, Stripes lets you send a ForwardResolution (OK status), Redirect, or Streaming (JSON, file, etc). The Redirect-after-POST pattern is implemented nicely with the idea of flash scope (3/4 down the page).
Forms validation: I can create custom validator (or choose from existing) and add it to almost each component. 3rd-party libraries have sets of custom ajax-validators. Standard validators work only after page is submitted. Actually, I don't like how validation in JSF works. Too much magic there. Many standard components (or maybe all of them) have predefined validation and it's impossible to disable it (Maybe not always, but I met many problems with it).
Stripes allows validation in annotations on the instance variables on the ActionBean. They allow some defaults, required, maxlength, etc. or you can always create your own. The default is easy to add and flexible, while there is always the ability to make something completely customized.
Ajax support: many 3rd-party libraries (MyFaces, IceFaces, OpenFaces, AnotherPrefixFaces...) have strong ajax support and it works pretty well. Until you meet a problem. Too much magic there as well. It's very difficult to make it work if it doesn't work but you've done right as it's described in the manual.
This was my big problem with the JSF way of doing things. Even if you did get the widget right, you're still stuck with THAT widget. With Stripes, you can use whatever latest and greatest Jquery has to offer, and as long as you send the right GET or POST to the server, stripes knows what to do with it and can easily send JSON back. I think component frameworks fit a niche a few years ago much better when AJAX was hard, but JQ makes it so easy now.
User-friendly URLs: people say that there are some libraries for that exist. And it can be done with filters as well. But I've never tried. It seems too complex for the first look.
#UrlBinding, it's as easy as that.
My answer is not the one you want to hear: Don't switch from Component Framework to action framework
I switched the other way around after many years of action framework development and I'm never going back.
Of the 8 use cases you mentioned, only one comes to mind where Action frameworks are obviously better, and that is URL design / friendly URLs. It can be done in component frameworks as well, but much easier in Action Frameworks (especially in Stripes where you just annotate your ActionBean with the url).
I would advise you to try wicket, it is very easy to learn (much easier than JSF) and it let's you re-use many existing components as well.
I have a custom SharePoint application page deployed to the _layouts folder. It's a custom "new form" for a custom content type. During my interactions with this page, I will need to add an item to my list. When the page first loads, I can use SPContext.Current.List to see the current list I'm working with. But after I fill in my form and the form posts back onto itself and IsPostBack is true, then SPContext.Current.List is null so I can't find the list that I need to add my stuff into.
Is this expected?
How should I retain some info about my context list across the postback? Should I just populate some asp:hidden control with my list's guid and then just pull it back from that on the postback? That seems safe, I guess.
FWIW, this is the MOSS 2007 Standard version.
Generally speaking I try and copy whatever approach the product group has taken when looking to add functionality of my own. In this case they add their own edit/view/add pages via the list definition itself.
I built a solution that also needed its own custom "New" form, not open source unfortunately, though if you are interested you can download it, its called "Tagged Links" (Social Bookmarking for SharePoint) and you can find some links on my blog.
To give you a few hints and tips, the following should set you off in the right direction:
Created a new list definition.
Created a new Content Type In the content type you can define your own "FormTemplates" that references a Rendering Template which determine what gets displayed in the "Middle" bit of those forms.
Copied the standard Rendering Template, but then made the changes to it that I
needed.
Wrapped it all up in a solution, and deployed.
My Rendering Template actually included an overridden "Save" Button where I did a lot of the extra work I needed to do during the save.
Anyway, it is a little too much work in my opinion but, I think, it most closely matches the standard approach taken by the product developers. Let me know if you need more detail and I will see if I can put together a step-by-step blog post, but hopefully this gets you off on the right direction.
I would be surprised if you could do something in a _Layouts file that you can't do in a forms template. You have pretty much the same technologies at your disposal.
Looking at the way SharePoint works with ListItems and Layouts pages (for example "Manage Permissions" on a list item), I can see that they pass some variables in via querystrings:
?obj={76113B3A-FABA-4389-BC85-4BB2CC5AB423},6,LISTITEM&List={76113B3A-FABA-4389-BC85-4BB2CC5AB423}
Perhaps they grab the context back each time programmatically using these values.
I'm not using a custom "new form", so this might not apply. I added an event receiver to my custom content type and then do my custom code in the ItemAdded or ItemAdding events. This code fires when the event is added to a list. You can use the event receiver properties to get to the parent List, Web, and Site.
I'd like to think my issue is "special" here, since I am using a custom form. I chose to use a custom form rather than a custom FormTemplate simply because I'm doing a lot of stuff that's not very SharePoint list-like (making ajax calls to get info from a third-party app then generating some dynamic form elements based on that ajax result, then subsequent processing of that data on postback). I thought it'd be a nightmare to try this within the usual custom rendering template mechanism.
I also don't think I can supply the custom form declarations in the list definition itself, because I have multiple content types associated with this list, and each content type has its own custom form (the other type is thankfully much simpler).
Actually, my simple way of keeping the list guid in my hidden field was a very low impact way to address this specific problem. My main concern is that I'm not sure why the SPContext just loses all its usefulness when I postback here, which makes me think I'm doing something wrong.
An obscure puzzle, but it's driving me absolutely nuts:
I'm creating a custom Information Management Policy in MOSS. I've implemented IPolicyFeature, and my policy feature happily registers itself by configuring a new SPItemEventReceiver. All new items in my library fire the events as they should, and it all works fine.
IPolicyFeature also has a method ProcessListItem, which is supposed to retroactively apply the policy to items that were already in the library (at least, it's supposed to do that for as long as it keeps returning true). Except it doesn't. It only applies the policy to the first item in the library, and I have absolutely no idea why.
It doesn't seem to be throwing an exception, and it really does return true from processing that first item, and I can't think what else to look at. Anyone?
Edit: Cory's answer, below, set me on the right track. Something else was indeed failing -- I didn't find out what, since my windbg-fu isn't what it should be, but I suspect it was something like "modifying a collection while it's being iterated over". My code was modifying the SPListItem that's passed into ProcessListItem, and then calling SystemUpdate on it; as soon as I changed the code so that it created its own variable (pointing at the exact same SPListItem) and used that, the problem went away...
There's only a couple of things I can think of to try. First, are you developing on the box where you might be able to use Visual Studio to debug? So just stepping through it.
Assuming that's not the case - what I'd do is fire up WinDBG and attach it to the process just before I registered the policy. Turn on first chance exceptions so that it breaks whenever they occur. you can do that by issuing the command "sxe clr" once it is broken in. Here's a little more info about WinDBG:
http://blogs.msdn.com/tess/archive/2008/06/05/setting-net-breakpoints-in-windbg-for-applications-that-crash-on-startup.aspx
What I'd do is then watch for First Chance exceptions to be thrown, and do a !PrintException to see what is going on. My guess is that there is an exception being thrown somewhere that is causing the app to stop processing the other items.
What does the logic look like for your ProcessListItem? Have you tried just doing a return true to make sure it works?
Some nice ideas there, thanks. The Visual Studio debugger wasn't showing an exception (and I've wrapped everything in try/catch blocks just in case), but I hadn't thought of trying Windbg...