比较两个列表C＃

Question

I have entity which is as follows

public class A
{
    public virtual int Id { get; set; }
    public virtual string AccountName { get; set; }
    public virtual string AccountId { get; set; }
    public virtual Status Status { get; set; }
    public virtual IList<Service> Services { get; set; }
}

I have another list which is of type Services which i want to compare with entity A.Services and get only those results of A which are matching (the same).

I want a lambda express or some way

Answer 1

You can have you class implement IEquatable, and then use Linq Intersect.

public class A : IEquatable<A>
{
    public virtual int Id { get; set; }
    public virtual string AccountName { get; set; }
    public virtual string AccountId { get; set; }
    public virtual Status Status { get; set; }
    public virtual IList<Service> Services { get; set; }

    //Implement IEquatable interfaces 
    //...
}

Note that when using LINQ Intersection call, use below one:

public static IEnumerable<TSource> Intersect<TSource>(
          this IEnumerable<TSource> first,
          IEnumerable<TSource> second,
          IEqualityComparer<TSource> comparer) //  <--- This is important

Answer 2

You can use Enumerable.Intersect method.

Produces the set intersection of two sequences by using the default equality comparer to compare values.

public class A : IEquatable<Service>
{
    public virtual int Id { get; set; }
    public virtual string AccountName { get; set; }
    public virtual string AccountId { get; set; }
    public virtual Status Status { get; set; }
    public virtual IList<Service> Services { get; set; }
}

var commonListofService = services1.Intersect(services2);

Answer 3

实现IEquatable<Service> ，然后您可以按以下方式使用Intersect

var common = services1.Intersect(services2);

Answer 4

Why not just have a method on class A that does it, then you don't need to bother with IEquatable...

public class A
{
    public virtual int Id { get; set; }
    public virtual string AccountName { get; set; }
    public virtual string AccountId { get; set; }
    public virtual Status Status { get; set; }
    public virtual IList<Service> Services { get; set; }

    public List<Service> GetCommonServices(A compareTo)
    {
         return this.Services.Intersect(compareTo.Services);
    }
}