How to easily extend Rendering Variants

Question

Is there a way to easily extend rendering variants logic?

My goal is to display the name of a parent item. Let's imagine that I'm using a Page List rendering and beside values from current context item fields I would like also to display the name of a parent item (the name can, for example, indicate my custom category name of something).

Is there a way to achieve this?

Answer 1

Yes, this is possible. There is an easy way to extend/add logic which is missing by implementing custom Variant Token.

This is an example implementation of ResolveParentName processor:

public class ResolveParentName : ResolveVariantTokensProcessor
{
    public override string Token => "$parentName";

    public override void ResolveToken(ResolveVariantTokensArgs args)
    {
        // this if statement is quite important in order to support this token in JSON Variants
        if (args.ResultControl != null)
        {
            args.ResultControl.Controls.Add(new LiteralControl
            {
                Text = args.ContextItem.Parent.Name
            });
        }
        else
        {
            args.Result = args.ContextItem.Parent.Name;
        }
    }
}

Do not forget about registering this processor:

<pipelines>
    <resolveVariantTokens>
        <processor type="YOUR_NAMESPAVE.ResolveParentName, YOUR_ASSEMBLY" resolve="true" />        
    </resolveVariantTokens>
</pipelines>

Here is an example usage:

As you can see this is a great place to add a lot of custom logic and extend Rendering Variants. In the above example, I'm just using one args.ContextItem.Parent.Name property but you can do whatever you need there.

UPDATE: Please use lowercased token names (instead of $parentName go with $parentname)