How dynamic or usage in EF Core Where?

Question

My sample code block is as follows, I have a string array. This array consists of dynamically not predetermined

var query = _dbContext.Table..;
List<string> arr= ...;
// output: arr=X,Y,Z

foreach (var item in arr)
{
    query = query.Where(f => f.XNumber.Contains(item))
}

The output of the expression I want to do should be like this

f.XNumber.Contains(item) or 
f.XNumber.Contains(item) or 
f.XNumber.Contains(item) or 

but every where causes an and operator. How can I convert it to OR operator? Is there a method like WhereWithOr?

Edit: my data looks like this:

XNumber:
12331X,
5113Y,
5123,
Z5123,
...

I'm trying to find items containing X or Y and Z in field XNumber

Answer 1

Using LINQKit's PredicateBuilder

var predicate = PredicateBuilder.New(query);
foreach (var item in arr)
{
    predicate = predicate.Or(f => f.XNumber.Contains(item));
}
query = query.Where(predicate);

Or my extension FilterByItems

query = query.FilterByItems(arr, (f, item) => f.XNumber.Contains(item), true);

Answer 2

What you're doing there is adding multiple Where clauses to the query. EF then combines them into a single Where claure that, obviously, joined by ANDs.

So youdneed to work with the inner predicate and add that to a single Where in your query.

An answer here suggests using PredicateBuilder

Answer 3

It could be done with a single Where, something like this:

query.Where(f => item.Any(i => f.XNumber.Contains(i)))

This will check if it can find a match for at least 1 item in your array.