Painted lady butterfly timelapse showing a butterfly turning out of its chrysalis.

First experimentation with timelapse stuff. This was a crummy old webcam attached to my computer.

Apparently YouTube took offence at my choice of copyrighted music. Bastards.

You may encounter a random error when using a custom Visual Studio SharePoint 2010 workflow. Everything appears OK, but when you go to edit the item that the workflow is running on, the EditForm fails to load and you see an error like:

`Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentNullException: Value cannot be null.
Parameter name: s

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[ArgumentNullException: Value cannot be null.
Parameter name: s]
System.IO.StringReader..ctor(String s) +10151478
System.Xml.XmlDocument.LoadXml(String xml) +51
Microsoft.SharePoint.Publishing.Internal.WorkflowUtilities.FlattenXmlToHashtable(String strXml) +90
...
`

Yet another SharePoint vagary. If you’re trying to deploy a feature and get the unhelpful error: “Error occurred in deployment step ‘Activate Features’: Object not set to an instance of an object” check the scope of the feature that you’re trying to deploy. I added a new feature to a project that had another working feature. Both were calling the Microsoft.Office.Workflow.Feature assembly but only one was failing and it was only after a lot of messing about that it turned out to be this innocuous little setting.

Quick tip: this plagued me for a while. You may develop a custom workflow which should only be associated with particular content types. You can deploy it to your site and then manually associate it to your content type. It’s possible to do this in code but the process isn’t as straight forward as it should be. Not to mention the fact that it’s infuriatingly hard to debug EventReceivers (“no symbols have been loaded” misery!).

A frequently asked question in the MSDN forums is “how you can get access to the user who is interacting with your workflow?”. For example, the user modifying a task. The workflow is likely running in a different context and/or session to your browser session so there’s not an obvious tie-up.

However, in this scenario, you can get the login name of the person who modified the SharePoint task, via the Executor property of the OnTaskChanged event. Simply bind the Executor property to a string (e.g., “taskLastModifiedBy”) and whenever the task changes, SharePoint will copy the user ID to this property in the format of DOMAIN\LoginName. You can then get an SPUser object for that login name with, e.g.

SPUser user = workflowProperties.Web.AllUsers[taskLastModifiedBy];

Note: On a related subject, and the thing that prompted this post - if you’re trying to update a Person or Group field on your workflowProperties.Item, then you must pass it an SPUser object! This is bizarre, because other types of list (e.g, the task list) you can pass it a string and SharePoint will do the rest. I spent ages and all kinds of different things and always getting the “Invalid data has been used to update the list item. The field you are trying to update may be read only.” error. Annoying.

One method for persisting data in a SharePoint environment is the use of Infopath forms. Infopath stores data in your form in XML format. I have a form which has a “comments” box where people add new comments as they progressively update the form and a “consolidate comments” box which shows all previous comments*. However, Infopath forms don’t natively support appending new data to existing data - and new comments added may blow away any previous comments.

Microsoft markets that Sharepoint Designer workflows are directly exportable to Visual Studio workflows. And in many ways, this is absolutely true. It’s trivial to create a .wsp from an SPD workflow and import it to VS. However, if you then inspect the workflow that has been created for you, a little concern would not be underestimated. If your SPD workflow was what you wanted, then you could be reasonably confident that its VS version would do the same job. But presumably your reason for importing to VS is because you need more control over the workflow in the longer term, in which case, you’re likely to be left underwhelmed by what the import process creates for you. Imagine creating a webpage in Microsoft Word and you’ll get the drift.

So when faced with a similar proposition, recreating the workflow in Visual Studio from scratch immediately became apparent as the best solution. After all, the intent and purpose of the workflow was clear; recreating it in VS ought to have been a doddle. However, to complicate matters, the SPD workflow used Infopath edit forms. This turned out to be easy in SPD, but non-trivial in Visual Studio. Getting an Infopath form to register with a VS workflow project requires various items, that VS may not do automatically for you.

Quick hint about debugging SharePoint projects in Visual Studio 2010. You may find a bizarre error where deploying projects/solutions is fine, but trying to debug doesn’t work. You see an error alert with the text:

“Could not load the Web.config configuration file. Check the file for any malformed XML elements, and try again. The following error occurred: The given key was not present in the dictionary.”

Checking the Web.config shows no malformed XML at all. One thing to check into is the configuration of alternate access mappings in Central Administration. For debugging to work, the Site URL property of your SharePoint project must match the URL of the Default zone for your web application.

It seems to me that every SharePoint developer, at some point in their career, will encounter this particular error. It’s one of those infuriatingly obtuse errors that could be caused by a multitude of different issues - either individually or cumulatively. In my case, I was in the middle of developing a SharePoint timer job and I had a particular piece of code that I wasn’t too sure about, and so wanted to test very quickly, over and over again - without the rigmarole of deploying/retracting solutions, hunting through Central Admin to run the job, etc. I just wanted to run this particular section of code against the SharePoint object model and see what happened. As is a common technique for this, I started up a fresh Console Application project, pasted in my code and figured that would be enough.

I finally got around to solving a longstanding irritation I’ve had with Finder. Well, when I say that, what I mean is, I posted the irritation to a forum, and some helpful folks there gave me the inspiration for the solution.

The irritation:

Quite often I copy a bunch of images off my phone on to my laptop. In Finder I open them up and use the quickview (using spacebar) to quickly view and delete items [using the keyboard only]

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