LINQ Distinct Query

Question

I have a C# application that loads a List of CLR objects called \"Tasks\". Each Task has the following properties:

public int ID { get; set; }
public int Typ         


        

Answer 1

You need to implement your own comparer:

public class TaskComparer : IEqualityComparer
{

    #region IEqualityComparer Members

    public bool Equals(Task x, Task y)
    {
        return x.TypeID == y.TypeID && x.TypeName == y.TypeName;
    }

    public int GetHashCode(Task obj)
    {
        return obj.TypeID.GetHashCode() + obj.TypeName.GetHashCode();
    }

    #endregion
}

Then use it like this:

var uniqueTasks = allTasks.Distinct(new TaskComparer());

EDIT: Hacked out some GetHashCode() thanks to Slaks who pointed out that GetHashCode is absolutely necessary (I guess it builds a HashTable internally)