Combining matching values in 2 observablecollections into a 3rd [WPF]

问题

Hello so I have one ObservableCollection that looks like this:

new time { Arrival = stringlist[0], Departure = stringList[1]};

new time2 { Arrived = stringlist[0], Departed = stringList[1]};

I would like to make a new ObservableCollection called datagridTime and insert into this ObservableCollection only records that match so lets say we have

Time `ObservableCollection`

Arrival   |     Departure
---------------------------------
10                 20
10                 30
10                 10

Time2 `ObservableCollection`

Arrival   |     Departure
---------------------------------
10                 20
10                 30
10                 20

datagridTime `ObservableCollection`

Arrived   |     Departed
---------------------------------
10                 20
10                 30

回答1:

Here is a short sample App which should do what you want.

The magic part is this:

public ObservableCollection<Person> People1 { get; } = new ObservableCollection<Person>()
{
    new Person("Donald", "Duck"),
    new Person("Daisy", "Duck"),
    new Person("Jack", "Daniels")
};

public ObservableCollection<Person> People2 { get; } = new ObservableCollection<Person>()
{
    new Person("Donald", "Duck"),
    new Person("Daisy", "Duck"),
    new Person("Jim", "Beam")
};

public IEnumerable<Person> PeopleInBothCollections
{
    get
    {
        foreach (var person in People1)
        {
            if (People2.Any(x => x.FirstName == person.FirstName && x.LastName == person.LastName))
            {
                yield return person;
            }
        }
    }
}

When ever you raise the PropertyChanged-event it should update your third list:

And here is the link to the example: https://github.com/timunie/MahApps.Metro.Examples/tree/master/src/MahApps.Metro.Examples/IntersectTwoLists

回答2:

You can use Intersect() Linq method, but you will have to implemente an EqualityComparer on your Time objects

Here you have the docs: https://docs.microsoft.com/en-us/dotnet/api/system.linq.enumerable.intersect?view=netcore-3.1

回答3:

This should work:

var time1 = new { Arrived = new List<string>(), 
                  Departure = new List<string>() };
var time2 = new { Arrived = new List<string>(), 
                  Departure = new List<string>() };

var time3 = new{ Arrived = time1.Arrived.Intersect(time2.Arrived),
                 Departure = time1.Departure.Intersect(time2.Departure) };

回答4:

Join can be used to solve this. This a solution for joining two collections based on some condition. In Your case u can replace the left and right anonymous collection with ObservableCollection

        var left = new[] {
            new { Arrival = 10, Departure = 20 },
            new { Arrival = 10, Departure = 30 },
            new { Arrival = 10, Departure = 10 }
        };

        //This collection contains duplicates hence needs to be removed either before or later joining the collection.

        var right = new[] {
            new { Arrival = 10, Departure = 20 },
            new { Arrival = 10, Departure = 30 },
            new { Arrival = 10, Departure = 20 }
        };

        var result =
                    left.Distinct() //remove duplicates
                    .Join(right.Distinct(), // Remove duplicates
                            right => new { right.Arrival, right.Departure },
                            left => new { left.Arrival, left.Departure },
                            (l, r) => new { r, l } // Matching elements in both collections use can return either of noth
                        ).ToList();//To list is called to execute the query and get result

Urge to check out more here

来源：https://stackoverflow.com/questions/62412876/combining-matching-values-in-2-observablecollections-into-a-3rd-wpf

标签

wpf

datagrid