Modify Attributes and Properties Using JSOM(CSOM)

Question

Before I describe the problem, I want to clarify that what I'm looking for is A generic way of updating various attributes/properties using JSOM.

I'm using an Office 365 dev account testing a SharePoint 2013 app. I'm trying to use JSOM to change a list column's attributes. Maybe I'm missing something here but what's the trick using JSOM on SharePoint 2013 to get/set specific list field attributes? For instance, I want to change the "Show field" in an "Attendees" column in a OOTB calendar list to be "Work email" instead of "Name (with presence)".

Before you jump the gun and tell me about get_Title() and get_required() and the other built in functions, let me clarify that I'm looking for something more generic where I can specify the exact attribute that maybe doesn't have a built-in function (like the "Show Field" example above).

I've tried using the get_schemaXml() and set_schemaXml() functions to get/set the XML directly like Anatoly Mironov does in his post. While this doesn't kick back errors, it also doesn't update anything. Does Office 365 even allow overwriting of XML schemas? Or is something out of whack w/ my code:

function testColPropChange(listName, fieldName, newTitle) {
     var subSiteUrl = 'https://tester.sharepoint.com/testSub';
     this.context = SP.ClientContext.get_current();
     var appContextSite = new SP.AppContextSite(this.context, subSiteUrl);
     this.web = appContextSite.get_web();
     var oList = this.web.get_lists().getByTitle(listName);
     var field = oList.get_fields().getByInternalNameOrTitle(fieldName);

     this.context.load(field, "SchemaXml");
     this.context.executeQueryAsync(Function.createDelegate(this, loadSuccess), Function.createDelegate(this, errorHandler));


    function loadSuccess() {
        var schema = field.get_schemaXml();
        var s1 = schema.replace('Required=/"FALSE/"','Required=/"TRUE/"');
        field.set_schemaXml(s1);
        field.update();
        this.context.executeQueryAsync(
           Function.createDelegate(this, schemaChanged), 
           Function.createDelegate(this, errorHandler));
    }
}

It's a simple query but I could still have jacked it up somewhere.

There has to be a simpler way of updating list column attributes using JSOM. Please advise.

======= UPDATE =========

While Rob's solution works for the instance I discussed above, I'm reopening this thread b/c I think it deserves more discussion.

I have many different properties other than the one mentioned that I can't seem to find a way to update (no native get/set methods). I've run across several but the two that I can remember off the top of my head are:

• "SelectionMode" (aka UserSelectionScope) on a people field
• "NavigateForFormsPage" on any list (to open forms in dialog instead of new page)

These props can be easily modified using C# or PowerShell with simple dot notation, so one would think it would be easy to change these in JSOM as well. But intellesense doesn't find anything. So what's the equivelant of obj.prop in JSOM? Anybody? Buehler... Buehler...

Answer 1

You need to cast the field object to the specific field type. In the case of the Attendees field in a calendar it's User of Group (SP.FieldUser). Once you have the specific field type you can usually get the property you need. In the case of the "Show field" for the User or Group field it's LookupField.

You can do the cast by calling the CastTo method of the ClientContext object.

var context = SP.ClientContext.get_current();
var hostContext = new SP.AppContextSite(context, hostUrl);
var web = hostContext.get_web();
var list = web.get_lists().getByTitle("Test Calendar");
var field = list.get_fields().getByInternalNameOrTitle("Attendees");

var userField = context.castTo(field, SP.FieldUser);
userField.set_lookupField("EMail");
userField.update();
context.executeQueryAsync(success, fail);

Answer 2

You need to break this into smaller chunks to stand a chance of being able to solve the issue. There are too many moving parts here. For example, try to set a column's schema XML to a hard-coded value. Does that work? If so, great. Next, working backwards from there, verify that you are actually getting the values you expect in your field and schema variables. Next, verify that the string replace operation is actually returning the results you expect.

If all that is working as you think it should, look at the event handlers. Is the loadSuccess event handler getting fired? Is the schemaChanged event handler getting fired? You didn't mention the actual path your code was taking, and that's an important thing to leave out.

When JSOM code fails there are two places where it might manifest itself:

First and most promiently, an executeQueryAsync call will return an error, and you can usually get a good handle on the problem by examining the error message returned to the error handler. Define your error handlers like this:

function errorHandler(sender, args)
{
    alert(args.get_message());
}

The alert will let you know right away what the issue is.

The second place you see errors in JSOM is when you try to access a property that is not loaded. This will become evident as a JavaScript error: the property has not been initialized. This means you are looking for something a previous call did not explicitly ask for. I would look at your field and schema variables to make sure they are being properly set.