當覆蓋Equals方法時，覆蓋GetHashCode爲何很重要？

問題：

Given the following class 鑑於如下課程

public class Foo
{
    public int FooId { get; set; }
    public string FooName { get; set; }

    public override bool Equals(object obj)
    {
        Foo fooItem = obj as Foo;

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

        return fooItem.FooId == this.FooId;
    }

    public override int GetHashCode()
    {
        // Which is preferred?

        return base.GetHashCode();

        //return this.FooId.GetHashCode();
    }
}

I have overridden the Equals method because Foo represent a row for the Foo s table. 我已經覆蓋了Equals方法，由於Foo表明的一排Foo桌上。 Which is the preferred method for overriding the GetHashCode ? 重寫GetHashCode的首選方法是？

Why is it important to override GetHashCode ? 重寫GetHashCode爲何很重要？

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解決方案：

參考一： https://stackoom.com/question/1YbA/當覆蓋Equals方法時-覆蓋GetHashCode爲何很重要
參考二： https://oldbug.net/q/1YbA/Why-is-it-important-to-override-GetHashCode-when-Equals-method-is-overridden