正确的方法重写equals（）和GetHash code（） [英] Correct way to override Equals() and GetHashCode()

问题描述

我从来没有真正前，所以我希望有人能告诉我正确实施的覆盖除什么这样做我的课（）和GetHash code（）。

I have never really done this before so i was hoping that someone could show me the correct what of implementing a override of Except() and GetHashCode() for my class.

我想修改类，这样我可以使用LINQ除（）方法。

I'm trying to modify the class so that i can use the LINQ Except() method.

public class RecommendationDTO{public Guid RecommendationId { get; set; }
public Guid ProfileId { get; set; }
public Guid ReferenceId { get; set; }
public int TypeId { get; set; }
public IList<TagDTO> Tags { get; set; }
public DateTime CreatedOn { get; set; }
public DateTime? ModifiedOn { get; set; }
public bool IsActive { get; set; }
public object ReferencedObject { get; set; }
public bool IsSystemRecommendation { get; set; }
public int VisibilityScore { get; set; }

public RecommendationDTO()
{
}

public RecommendationDTO(Guid recommendationid,
                            Guid profileid,
                            Guid referenceid,
                            int typeid,
                            IList<TagDTO> tags,
                            DateTime createdon,
                            DateTime modifiedon, 
                            bool isactive,
                            object referencedobject)
{
    RecommendationId = recommendationid;
    ProfileId = profileid;
    ReferenceId = referenceid;
    TypeId = typeid;
    Tags = tags;
    CreatedOn = createdon;
    ModifiedOn = modifiedon;
    ReferencedObject = referencedobject;
    IsActive = isactive;
}

public override bool Equals(System.Object obj)
{
    // If parameter is null return false.
    if (obj == null)
    {
        return false;
    }

    // If parameter cannot be cast to Point return false.
    RecommendationDTO p = obj as RecommendationDTO;
    if ((System.Object)p == null)
    {
        return false;
    }

    // Return true if the fields match:
    return (ReferenceId == p.ReferenceId);// && (y == p.y);
}

public bool Equals(RecommendationDTO p)
{
    // If parameter is null return false:
    if ((object)p == null)
    {
        return false;
    }

    // Return true if the fields match:
    return (ReferenceId == p.ReferenceId);// && (y == p.y);
}

//public override int GetHashCode()
//{
//    return ReferenceId;// ^ y;
//}}

我已经采取了看<一个href=\"http://msdn.microsoft.com/en-us/library/ms173147.aspx\">http://msdn.microsoft.com/en-us/library/ms173147.aspx但我希望有人能我自己的例子中告诉我。

I have taken a look at http://msdn.microsoft.com/en-us/library/ms173147.aspx but i was hoping someone could show me within my own example.

任何帮助将是AP preciated。

Any help would be appreciated.

感谢您

推荐答案

您可以在你的类像这样重写equals（）和GetHash code（）：

You can override Equals() and GetHashCode() on your class like this:

public override bool Equals(object obj)
{
    var item = obj as RecommendationDTO;

    if (item == null)
    {
        return false;
    }

    return this.RecommendationId.Equals(item.RecommendationId);
}

public override int GetHashCode()
{
    return this.RecommendationId.GetHashCode();
}

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