I have requirements to create a search interface that allows the end user to perform faceted search against an index. One of the requirements is to be able to do a range query against certain fields (that are configured at runtime by the content owner). The search is executed as part of a REST call and the results are returned to the front end for display.

Under normal circumstances, one would do a range query using the .Between() method in LINQ, like so:

var productQuery = PredicateBuilder.True<SearchResultItem>();
productQuery = productQuery.And(x => x[filterField].Between(lowerLimit, upperLimit, Inclusion.Both));

When I create the above predicate and pass it to the search context:

using (var context = ContentSearchManager.GetIndex(string.Format(IndexBaseName, Sitecore.Context.Database.Name)).CreateSearchContext())
    var searchResults = context.GetQueryable<SearchResultItem>().Where(productQuery).ToList(); 

The above throws a System.NotSupportedException with the message "Unsupported expression node type: ArrayIndex". After a bit of Googling, it appears that this might be a limitation of LINQ, which explains why most examples of calling .Between() don't use SearchResultItem and instead use a custom model where the range field is mapped to a property. I'm my case, since the fields can vary based on how the content editor configures which fields are used for these range queries, I need to find a way around this.

  • Can you try the following for the predicate: predicate.Or(x => x[filterField]).Between(lowerLimit, upperLimit, Inclusion.Both)); May 22 '18 at 18:56
  • That doesn't work since .Or is going to want a lambda function that returns a bool. Also predicate isn't defined. May 22 '18 at 19:48

So in simplifying my code for posting as a question here, I left out the fact that lowerLimit and upperLimit above were actually values coming from an arrary and were actually:

productQuery = productQuery.And(x => x[filterField].Between(range[0],range[1], Inclusion.Both));

Which is the actual source of the "Unsupported expression node type: ArrayIndex" message (which is exactly the issue in the linked Stack Overflow question.)

  • is this a solution to the question or an update? If its an update can you update the question, if its an answer can you clarify what the solution is please?
    – Richard Seal
    May 22 '18 at 21:02
  • 1
    I had to wait in order to mark my answer my own question as accepted. May 29 '18 at 19:44

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