Objects that are Visualforce field component resolvable?

Question

What does Visualforce field component resolvable mean?

I tried to bind columns editor to a list of custom Apex class instances, and naturally ran into this error. Rather than taking the workaround and breaking this up into inputXXX's I would prefer to modify the class to make it VF friendly. However, nobody seems to know what "Visualforce field component resolvable" means.

Do I need to decorate the class? Add specific metadata methods? Any ideas?

This is NOT a duplicate question. My question relates to the second part of the description provided by the error message, stating that inputfield needs SOQL objects OR Objects that are Visualforce field component resolvable, which is not covered by the other answer.

Example:

public class Item {
    public Boolean Selected { get; set; } 
}

public List<Item> Items;

VF

<apex:pageBlockTable value="{!Items}" var="item" >
    <apex:column headerValue="Select" >
        <apex:inputField value="{!item.Selected}" />
    </apex:column>
</apex:pageBlockTable>

Save error: Could not resolve the entity from value binding '{!item.Selected}'. can only be used with SObjects, or objects that are Visualforce field component resolvable.

To reiterate again, I know that inputField works with SOQL, what I want to know about is the meaning and implementation of the second part of the error message. How can one go about making a custom class VF inputField friendly.

Answer 1

See @batterycord - inputfield can only be bound to SObject fields. Same with outputField

However, to exploit the user interface controls supplied by VF, you can consider using proxy sobjects

public class Item {
   public User u;   // the proxy object to provide a checkbox control
}


<apex:pageBlockTable value="{!Items}" var="item" >
   <apex:column headerValue="Select">
    <apex:inputField value="{!item.u.IsActive}" />
   </apex:column>
</apex:pageBlockTable>

Answer 2

We've only seen two things in the wild that are "Visualforce field component resolvable":

1. Schema.SObjectField
2. Schema.FieldSetMember

The FieldSetMember has to be used to dereference a specific field off a specific related SObject :(

Answer 3

I can't find offical documentation for this right now but it seems apex:inputField needs metadata to function correctly. And normal apex variables does not has this metadata. If you want to use inputField you can wrap an sObject then use it in inputField. (As being only method and the one you already use.)