Hallo Christian,
Wenn ich dich richtig verstehe, würde ich folgendes schreiben:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
class Program {
static void Main(string[] args) {
new Program().Test();
Console.ReadKey(true);
}
public async void Test() {
ContactsManager manager = new ContactsManager();
IQueryable<Contact> t =
await manager.GetContacts(c => c.LastName == "Bäcker" &&
c.Email.Contains("example.com"));
var result = t.ToList();
}
}
public class ContactsManager {
List<Contact> contacts = null;
public ContactsManager() {
this.contacts = new List<Contact> {
new Contact { FirstName = "Tom", LastName = "Bäcker", Email = "tom@albert.de", PhoneNo="09999" },
new Contact { FirstName = "Jenny", LastName = "Bäcker", Email = "jenny@example.com", PhoneNo="09999" },
new Contact { FirstName = "Hannes", LastName = "Domeyer", Email = "hannes@domeyer.de", PhoneNo="09999" }
};
}
public Task<IQueryable<Contact>> GetContacts(Expression<Func<Contact, bool>> selectionCriteria) {
TaskCompletionSource<IQueryable<Contact>> tcs = new TaskCompletionSource<IQueryable<Contact>>();
IQueryable<Contact> query = contacts.Where(selectionCriteria.Compile()).AsQueryable();
tcs.SetResult(query);
return tcs.Task;
}
}
public class Contact {
public string FirstName { get; set; }
public string LastName { get; set; }
public string PhoneNo { get; set;}
public string Email { get; set;}
}
}
Gruß
Marcel
