Class PropertyComparer<T, P>

Implements IEqualityComparer<T> for the specified type T comparing the specified property

Inheritance
object
PropertyComparer<T, P>
Implements
Inherited Members
Namespace: LemonEdge.Utils
Assembly: LemonEdge.Utils.dll
Syntax
public class PropertyComparer<T, P> : IEqualityComparer<T>
Type Parameters
Name Description
T

The type to compare equality for
P

The return type of the property to use to compare equality on
Remarks

This is useful in Linq functionality where you want distinct lists of items that have certain property values. For example:

public class MyItem 
{
    public int Value { get; set; }
    public string Group { get; set; }

    public override string ToString() => Value.ToString();
}

private IEnumerable<MyItem> GetFirstItemOfEachGroup()
{
    var items = new List<MyItem>() { new MyItem { Group = "1", Value = 1 }, new MyItem { Group = "1", Value = 2 }, new MyItem { Group = "2", Value = 3 } };
    return items.Distinct(PropertyComparer<MyItem, string>.Create(x => x.Group));
}

Will return:

1,3

Constructors

PropertyComparer()

Declaration
public PropertyComparer()

Methods

Create(Func<T, P>)

Creates a new PropertyComparer that can compare two instances of type T and determine if their property values are equal

Declaration
public static PropertyComparer<T, P> Create(Func<T, P> prop)
Parameters
Type Name Description
Func<T, P> prop

A function that return the value of a specific property given an instance of type T
Returns
Type Description
PropertyComparer<T, P>

A new PropertyComparer that can compare if instances have the same property value or not

Equals(T, T)

Declaration
public bool Equals(T x, T y)
Parameters
Type Name Description
T x
T y
Returns
Type Description
bool

GetHashCode(T)

Declaration
public int GetHashCode(T obj)
Parameters
Type Name Description
T obj
Returns
Type Description
int

Implements

Extension Methods