I'm having troubles with the Except() method.
Instead of returning the difference, it returns the original set.
I've tried implementing the IEquatable and IEqualityComparer in the Account class.
I've also tried creating a separate IEqualityComparer class for Account.
When the Except() method is called from main, it doesn't seem to call my custom Equals() method, but when I tried Count(), it did call the custom GetHashCode() method!
I'm sure I made a trivial mistake somewhere and I hope a fresh pair of eyes can help me.
main:
IEnumerable<Account> everyPartnerID =
from partner in dataContext.Partners
select new Account { IDPartner = partner.ID, Name = partner.Name };
IEnumerable<Account> hasAccountPartnerID =
from partner in dataContext.Partners
from account in dataContext.Accounts
where
!partner.ID.Equals(Guid.Empty) &&
account.IDPartner.Equals(partner.ID) &&
account.Username.Equals("Special")
select new Account { IDPartner = partner.ID, Name = partner.Name };
IEnumerable<Account> noAccountPartnerID =
everyPartnerID.Except(
hasAccountPartnerID,
new LambdaComparer<Account>((x, y) => x.IDPartner.Equals(y.IDPartner)));
Account:
public class Account : IEquatable<Account>
{
public Guid IDPartner{ get; set; }
public string Name{ get; set; }
/* #region IEquatable<Account> Members
public bool Equals(Account other)
{
return this.IDPartner.Equals(other.IDPartner);
}
#endregion*/
}
LambdaComparer:
public class LambdaComparer<T> : IEqualityComparer<T>
{
private readonly Func<T, T, bool> _lambdaComparer;
private readonly Func<T, int> _lambdaHash;
public LambdaComparer(Func<T, T, bool> lambdaComparer) :
this(lambdaComparer, o => o.GetHashCode())
{
}
public LambdaComparer(Func<T, T, bool> lambdaComparer, Func<T, int> lambdaHash)
{
if (lambdaComparer == null)
throw new ArgumentNullException("lambdaComparer");
if (lambdaHash == null)
throw new ArgumentNullException("lambdaHash");
_lambdaComparer = lambdaComparer;
_lambdaHash = lambdaHash;
}
public bool Equals(T x, T y)
{
return _lambdaComparer(x, y);
}
public int GetHashCode(T obj)
{
return _lambdaHash(obj);
}
}
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