How do I get the value from a SPFieldBoolean object? Do I simply cast it to a boolean or do I need to do something further with it?
I am fetching it in an EventReceiver class during an ItemAdded event from properties.ListItem["fieldname"].
If there is a chance the field might not exist (and be null), how do I check for that?
The value is already a bool, you just need to type-cast it. All fields provide values in their native value-type — see also SPField.FieldValueType property that gives you the actual type in case you need to inspect it on runtime.
To make sure the field is contained in the list, just use the SPFieldCollection.ContainsField method on your list's Fields collection.
Related
Quick question.
I have a custom two-option field on an entity, with "Yes"/"No" as the values; "Yes" has the underlying value 1, while "No" has the underlying value 0. I've set the default value for this field to "Yes". However, when I create new entity records, the field always gets the value "No" (0 in the database). It seems to be ignoring the default value I've set. Why?
The field is not present on any of the entity forms, as it's only used in underlying plugin code. Should that matter?
Are you creating a new record for this entity using code that uses the strongly-typed objects? If so, when you create a "new" entity in code, I'm guessing the class itself is setting that field to "false" by default. I don't think those generated classes respect the default values in the metadata. I also think that all fields are submitted on a create when you use these generated classes. That means that your class is setting it to "no" by default and then on create, the system thinks that you explicitly set it to "no" so default values are not applied. I think you need to explicitly remove that attribute from the attribute collection of your entity before you create it. That way the system should respect the default value on create. Sorry for all the "I thinks" but I'm not in a place that I can test or verify all of this. :)
I am working with xpages components and it is hard for me to quess when the getComponent("comp").getValue() returns null or when returns "" (empty string).
Is there a way to tell? Are there components which return null when other components return ""?
A component will have a null value if the value property has not been assigned. That can happen if the it's bound to a field on a document and that document does not yet have the field, e.g. it's a brand new document. It can also happen if it's bound to a scoped variable that hasn't been set yet.
It's best practice to bind, wherever possible, to the data source rather than go via the component. This way document1.getItemValueString("myField") will return a blank string if myField hasn't been set on document1, as well as if myField's value is "". Also, if in the future youo delete the component comp, the compiler won't (and can't) tell you you're calling that component in SSJS and you'll get a runtime error. If you're using document1.getItemValueString("myField"), it will still work.
Plus, as Tim Tripcony said, it's slower https://twitter.com/timtripcony/status/359532216382001152 and this blog post goes into much greater depth on why to talk to data not components http://www.timtripcony.com/blog.nsf/d6plinks/TTRY-942UPQ
I ran across a problem for which I found no documented solution, but inadvertently found the solution myself. So I wanted to document this here for others who may encounter the same problem.
I was using a CAML query within SPServices to retrieve list items, then referencing "ows_{fieldname}" as usual to retrieve the field value for each list item. The field value was reported as "undefined" for all items. I quintuple-checked that I was specifying the proper name of the field and that my query was properly constructed.
I eventually discovered that the fields I was trying to reference were not displayed in the default view of the list. As soon as I changed the list properties to include the fields in the default view, the proper field values were returned within my javascript.
I don't know how much of Sharepoint's underpinnings work, but I was very surprised at my finding because it implies that the SPServices GetListItems method gets its data from the list's default view, not the actual underlying list. I realize I could be wrong in this interpretation, but I imagine others could run into this same problem.
The default, although unreliable, way GetListItems works is that it's suppose to returns all fields displayed on the default list view if you don't specify ViewFields on input. This is unreliable. Although you got it working - now - someone could come along later and change the default view thus breaking your sweet customization. Bummer. :)
I suggest always listing the ViewFields you are interested in on the GetListItems method. This ensures that your will get them if they are set. That's right. You could still get rows with an undefined field. This happens mostly on fields of type Lookup that are not set on a row.
Hope this helps you understand what is going on. Over the years I have created my own wrappers around SPServices to ensure I get back a reference to all fields requested, even if they are not in the response by Sharepoint.
When using SPServices' GetListItems method, be sure that any fields that you reference from the list are included in the list's default view, otherwise an undefined value will be returned.
I'm trying to make a field read only when a given value is selected from a PickList.
I'm using a flag that is set to Y when the list has that value, and N otherwise.
I created a Business Component User Prop with the name Field Read Only Field: MyField set to the flag.
Thing is, this works with the vanilla component but it wont work on my custom component.
I can't figure out what is going on, the properties of the fields and flag are exactly the same. It should work...
Thanks for any help you can give me.
That user property is only supported on the business component class CSSBCBase and its subclasses. My guess is that you probably used CSSBusComp as the class of your business component. CSSBusComp is actually a superclass of CSSBCBase, and is very minimal and does not support Field Read Only Field. If that's the case, change it to CSSBCBase and you should be good to go.
Other option is that- if the record become read-only when the picklist value is being selected- that you'll need to make the picklist field Immediate Post Changes to be sure the user property is triggered.
In SharePoint many fields id-value pairs that are formatting like the following id;#value. This is further complicated with fields like multi-lookup where when extracting the value of that field can yield results like id_1;#value_1;#id_2;#value_2;#id_3;#value_3
I am wondering if there is any known built in function that will simplify this process and at the very least remove the IDs from the value.
Field value objects are stored as strings in the Sharepoint database. For simple values (e.g. "Hello world") this is simple enough. But for complex field values - such as an ID/value pair, how to store the entire value as a single string is obviously more complex as well. Each field value class in Sharepoint is responsible for its own storage implementation. ToString() is responsible for writing a string representation of the value; while the field value's constructor takes a string and is responsible for parsing that and setting all the properties on itself appropriately.
For example, the SPFieldUrlValue (which represents an description) has Url and Description properties. Creating a new SPFieldUrlValue(string fieldValue) object will parse the value and set the properties accordingly.
In order to get a true/correct (and often strongly-typed!) representation of the field value, you must know what type the field is, and what that field's value class is.
The SPField class has many derived classed
For example assuming a Lookup field type (that uses the ID;#value) you can check SPField.Type == SPFieldType.Lookup and then cast SPField to SPFieldLookup and use its overriden methods to get the records value.
See Custom Field Value Classes for more details
Also - If I remember correctly (I can't check this right now so DYOR) you can call .ValueAsText and .ValueAsHtml on the base SPField object and it will remove ID;# from the values.