Using PrincipalSearcher to find users with “or” parameters

It’s obviously not possible, here is a workaround:

List<UserPrincipal> searchPrinciples = new List<UserPrincipal>();
searchPrinciples.Add(new UserPrincipal(context) { DisplayName="tom*"});
searchPrinciples.Add(new UserPrincipal(context) { SamAccountName = "tom*" });
searchPrinciples.Add(new UserPrincipal(context) { MiddleName = "tom*" });
searchPrinciples.Add(new UserPrincipal(context) { GivenName = "tom*" });

List<Principal> results = new List<Principal>();
var searcher = new PrincipalSearcher();
foreach (var item in searchPrinciples)
{
    searcher = new PrincipalSearcher(item);
    results.AddRange(searcher.FindAll());
}