Dapper supports IN statements being passed an array:

SELECT x, y FROM A WHERE z IN @ids

Works if you pass in a parameters object containing a property called ids that is a list/array of some sort (see https://github.com/StackExchange/dapper-dot-net#parameterize...).

On SQL 2016 this uses STRING_SPLIT across an nvarchar(MAX) which makes it effectively unbounded. Earlier versions and other platforms have restrictions on the number of elements in the array/list.