// You could use a nested Any() for this check which is available on any Enumerable:
bool hasMatch = myStrings.Any(x => parameters.Any(y => y.source == x));
// Faster performing on larger collections would be to project parameters to source and
// then use Intersect which internally uses a HashSet<T> so instead of O(n^2) for the
// first approach (the equivalent of two nested loops) you can do the check in O(n) :
bool hasMatch = parameters.Select(x => x.source)
.Intersect(myStrings)
.Any();
// source: https://stackoverflow.com/a/11092955