Kategoriarkiv: jslink

Update Field.JSLink using JSOM or REST

Today I have just a little code snippet to share. This code snippet shows how to update the JSLink property for an existing field using JSOM and REST. For REST I use sharepoint-utilities.

A couple of notes, to update a field we need:

  • A POST request
  • with a header ‘X-HTTP-Method’: ‘MERGE’
  • with __metadata: { type: SP.Field } and JSLink property in the payload
  • and X-RequestDigest‘ header (but it is nicely handled by sharepoint-utilities)

Provisioning Google Maps JSLink with SPMeta2

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Among PnP Samples there is a solution for using Google Maps. Great solution where where you can pick a point on a map and define a spacial area on the map. Unfortunately it is a sandbox solution. I rewrote it to a code based template with SPMeta2 Framework. Now it can be installed on any site very easily, without needing UserCode Service and a cumbersome process of uploading a wsp package and activating it. The code is very simple, you can see it on github.

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Let’s take a look at it. It does not contain a single line of SharePoint Legacy XML. There are following SharePoint artefacts that are getting provisioned:

  1. Two site columns (Location Point and Location Area)
  2. A SharePoint List (Locations) with two additional fields mentioned above
  3. Google Maps code in and CSR in a jslink file
  4. Auxiliary pages for selecting points and areas on the map.

Field Definitions

In SPMeta2 everything is separated in meaningful definitions. First we define our fields. The preferred place in the VS solution is Definitions – IA – Fields.

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List Definitions

Then we define our List – Locations. That is also a SPMeta2 Definition. List Definitions reside in Definitions – IA – Lists. We do not add fields in our list definition. The fields are added while “assembling” the model.

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ListView Definitions

ListView Definitions are also in the Definitions – IA folder. We inherit from the OOB AllItems view:

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Modules (a.k.a. Files)

Resource files like javascript, css, aspx, html and so on are Modules. They are in the “Modules – Implicit” folder. The internal structure is copied to the web folder. The upload of files is easy and is defined in the web model, see next section.

Web Model

Now it is time to pick the definitions and create a model. The most common model is a Web Model. The model is created programmatically and relies on “Add” methods: AddField, AddList and so on:

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Provisioning

The actual provisioning is the most fun, it is easy and straight forward, it takes models and deploys it to a SharePoint site. You can easily switch between SSOM and CSOM.

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Distribution

Another bonus of SPMeta2 Provisioning Framework is the ability to serialize and deserialize models to XML or JSON. In our project we define SharePoint Applications as SPMeta2 models serialized in XML and make them available for installation on any SharePoint Site.  A SharePoint Application is a meaningful collection of SharePoint artefacts that becomes an entity and solves a business need.

Summary

This Maps solution is a simple solution, but it is a very powerful one, originally created by the PnP team. If we just redesign the Provisioning Part, it becomes awesome. SPMeta2 provides a solid, well defined, easy-to-understand framework for define code-first models for SharePoint Applications.

Bypass all custom jslink

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Client Side Rendering (CSR) and jslink are great for customizing lists and forms in SharePoint. In my current project we use it a lot of it. A disadvantage of that path, although, is that it might occur javascript errors, during the development phase, but also in production. We do, of course, our best to leverage the best jslink code, but unfortunately we have to live with the fact that errors can occur, especially when we use it for NewForm, EditForm, DisplayForm and View (in list and grid).

If an error occurs, it won’t stop the rest of javascript (it is wrapped in try and catch by SharePoint), but the fields will still not function as intended. It can also be some “corrupt” or old data in the field value that will “break” the jslink code.

I would like to suggest one little fix, an idea I’ve come up to in my jslink-heavy project:

Use a custom url parameter to stop all custom jslink execution.

The query string parameter can be called bypasscustomjslink=true

In every custom jslink, start with this line of code:

That’s it. If you have this in place, you can just manually add this to your url in browser:

or

Then all the customized fields and views will be uncustomized until bypasscustomjslink=true is removed. While viewing and editing list items in this uncustomized mode, you can access and repair data as if you never had adjusted it with jslink.

Using this does not mean you can “relax” and start writing crappy code. You still have to produce good code and anticipate all possible errors. bypasscustomjslink is just a convenient “emergency exit” aimed for developers and support to quickly solve problems without needing to reset the JSLink property on fields and list views.

Client Side Rendering with Async dependencies

Yesterday I asked a question on SharePoint StackExchange:

I also asked Elio Struyf on Twitter:

Good idea, Elio Estruyf! Now I want to try it out.

Preparations

In this case I’ll be using my example from my blog post yesterday:

Drag and Drop Image using Client Side Rendering

I have created a new list and added a lookup field to my previous list. What I get is a Title of the lookup item, but not my custom field called DragAndDrop. In my test I will try to load the DragAndDrop Image using an ajax call and rendering it after Client Side Rendering is done with my item.

To be complete, I want to show some screenshots for my lookup field:

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It will result in this OOTB rendering:
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Trying out CSR with async dependencies

While working with jslink, first of all I want to show a loading image instead of an empty html element, to show that something is loading:
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Here is the skeletton of the jslink file:

Making an ajax call

Next step is to initiate an ajax call. I am trying to avoid the jQuery dependency. There is so much you can do with the built-in javascript functions. For making an ajax call I am using SP.RequestExecutor.js

Here is the result:

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The code should be quite self explaining:

Next steps and further considerations

It seems to work, although I have some considerations:

  1. What happens if the data from the ajax call is retrieved before Client Side Rendering is done (then the container is not rendered yet). Even if the risk for that is low, it should be handled properly.
  2. It would be good to have a consistent look and feel in the Display form and in the list view. To make it possible, following should be done:
    1. We must create references to html elements (containers) with unique ids, need to implement logic for generating ids and keeping track of the right elements.
    2. Ajax calls should be bundled, otherwise it will hugely impact the performance, even in a list view with 30 items.