ResolveRenderingContext.cs

using Sitecore.Mvc.Pipelines.Response.RenderRendering;
using Sitecore.Mvc.Presentation;

namespace Sitecore.Foundation.Multisite.Pipelines
{
    public class ResolveRenderingContext : EnterRenderingContext
    {
  
        protected override void EnterContext(Rendering rendering, RenderRenderingArgs args)
        {

            //Make your changes to the items that are used to build the context here
            if (args.PageContext != null &&
                args.PageContext.Item != null &&
                (args.Rendering.DataSource.Contains("query")))
            {
                var innerQuery = args.Rendering.DataSource.Replace("query:", "");
                var datasourceItem= Context.Item.Axes.SelectSingleItem(innerQuery);
                //replacing the datasource with Item Id of the queried item
                if (datasourceItem != null)
                    args.Rendering.DataSource = datasourceItem.ID.ToString();
                else
                    Sitecore.Diagnostics.Log.Error("Resolving Rendering Context >> " + args.Rendering.DataSource + " Not Found", this);
            }
            //build the context using the existing functionality
            base.EnterContext(rendering, args);
        }
    }
}