I’ve been involved with SharePoint for a very, very long time, since 2001 in fact. One of the basic truths that we old timers learned very early on was that an internal list column name wasn’t necessarily the same as its display name. For the most part, when a column is created, the name is the same, but any subsequent changes to the name only affect the way that it is displayed, and the original name stays the same. In fact, even on creation, if a space is used in the name, when saved, the internal name replaces the space with “_x0020_”. This is why it is a best practice to create all entities using no spaces, and then edit them later adding any desired spaces. It just makes life easier for people working with internal names.
Who works with internal names? Anyone that needs to extend SharePoint really. Any explicit reference to a SharePoint column normally needs its internal name. Given that display names are editable, this makes sense. Because of this, for a long time, I’ve gotten used to being careful about column names when creating them, so that it’s easy to reference them later.
The way that the slider works is by reading entries from a custom list. This list contains a couple of columns named HTML and Picture. I added a third named DestinationURL to make the image clickable. I created this new list, and then edited it using the “traditional” method of accessing List settings. The HTML and DestinationURL fields were simple text fields, and the Picture field was a Picture column. Once created and populated, everything worked great.
Next up, I had to repeat this on a different site. I couldn’t save the custom list as a template because the destination site was in a different language. I therefore decided to just go ahead and create another list manually, but this time, I added the field with the new SharePoint 2013 “Quick List Editor”. If you haven’t seen it before, it shows up as a “+” symbol when you use it.
You simply click the “+” symbol, choose the column type type the name of your column and keep going. If you choose the “More Column Types…” option, you are presented with the traditional column creation dialog box. I needed to use this for my “Picture” column.
Once complete, everything looked great.
I then went ahead and populated the list with content, and implemented the slider code on the home page. The trouble is that it wouldn’t work. After tearing out my hair a fair bit, it appeared that while the picture column was returning data, the HTML and DestinationURL columns were not. I found this very odd as I had been careful with the names, and this was a new list. Additionally, the Picture type column is more complex. If any column was going to give me grief, I’d think it’d be that one.
Finally, I decided to confirm the column names, because I don’t trust myself. The easiest way to do that is to go into List Settings, hover the mouse over the column definition, and check the destination URL that pops up as it contains “Field=fieldname” in it. I then did so for my HTML field:
What? The fieldname is “vtwo”. Upon checking, the DestinationURL field had an equally random name (“vn1m”). However, the Picture field was “Picture” as expected. How did this happen? Why did it happen to only two columns?
As it turns out, it’s the quick list editor is the culprit. When you add columns using it, it has no mechanism to check your column name against existing columns, so it doesn’t even try – it just forces a random column name. However, when you choose “More Column Types” it loads the traditional column editor, which does have such control, and therefore, my Picture field worked as expected.
After going back, deleting and recreating my two columns (and repopulating the content), everything worked as expected.
Lesson learned – when changing a list schema, stick to the list settings interface. Don’t use the Quick List Editor for adding new columns.