How to convert this foreach loop into Linq code?

Question

I am new one with Linq and I would like to modify my old c# code to use Linq. The idea of this code to select all tables where it\'s not set and reference’s field PrimaryTab

Answer 1

var tables = dbServer.Tables
    .Where(t => !t.IsSet)
    .SelectMany(t => t.References)
    .Where(r => r.PrimaryTable == "myTable")
    .ToList();

Assuming tables is a List

EDIT: As the comment points out, this isn't the same as the original - it looks like what you actually want is this:

var tables = dbServer.Tables
    .Where(t => !t.IsSet && t.References.Any(r => r.PrimaryTable == "myTable"))
    .ToList();

This will give you all the tables which have a reference whose PrimaryTable is 'myTable' which assumes that there will only be one matching reference table. Otherwise you could have the same table added multiple times.