Distinct()如何在对象列表中查找唯一元素

Question

有一个非常简单的类:

public class LinkInformation
{
    public LinkInformation(string link, string text, string group)
    {
        this.Link = link;
        this.Text = text;
        this.Group = group;
    }

    public string Link { get; set; }
    public string Text { get; set; }
    public string Group { get; set; }

    public override string ToString()
    {
        return Link.PadRight(70) + Text.PadRight(40) + Group;
    }
}

我创建了这个类的对象列表,包含多个重复项.

所以,我尝试使用Distinct()获取唯一值的列表.

但它不起作用,所以我实施了

IComparable<LinkInformation>

    int IComparable<LinkInformation>.CompareTo(LinkInformation other)
    {
        return this.ToString().CompareTo(other.ToString());
    }

然后...

IEqualityComparer<LinkInformation>

    public bool Equals(LinkInformation x, LinkInformation y)
    {
        return x.ToString().CompareTo(y.ToString()) == 0;
    }

    public int GetHashCode(LinkInformation obj)
    {
        int hash = 17;
        // Suitable nullity checks etc, of course :)
        hash = hash * 23 + obj.Link.GetHashCode();
        hash = hash * 23 + obj.Text.GetHashCode();
        hash = hash * 23 + obj.Group.GetHashCode();
        return hash;
    }

使用的代码Distinct是:

    static void Main(string[] args)
    {
        string[] filePath = {   @"C:\temp\html\1.html",
                                @"C:\temp\html\2.html",
                                @"C:\temp\html\3.html",
                                @"C:\temp\html\4.html",
                                @"C:\temp\html\5.html"};

        int index = 0;

        foreach (var path in filePath)
        {
            var parser = new HtmlParser();

            var list = parser.Parse(path);

            var unique = list.Distinct();

            foreach (var elem in unique)
            {
                var full = new FileInfo(path).Name;
                var file = full.Substring(0, full.Length - 5);
                Console.WriteLine((++index).ToString().PadRight(5) + file.PadRight(20) + elem);
            }
        }

        Console.ReadKey();
    }

要做什么Distinct()工作？

Answer 1

当你调用它时IEqualityComparer,你需要实际传递你创建的Disctinct.它有两个重载,一个不接受参数,一个接受一个IEqualityComparer.如果您不提供比较器,则使用默认值,并且默认比较器不会比较您希望它们进行比较的对象.