关于集合排序icomparer接口

liuyilin999 2010-09-29 09:29:43

关于集合排序icomparer接口



'实现了icomparer接口

Public Class Comparer

Implements IComparer

     Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer Implements IComparer.Compare

           Dim CC As New CaseInsensitiveComparer()

           Return CC.Compare(y, x)

     End Function

End Class



'排序

ArrayList.Sort(new Comparer)

请问为什么 ArrayList.Sort(new Comparer)会自己去执行Compare(x, y)方法
并没有调用里面的方法Comparer.Compare(x, y)
谢谢

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liuyilin999 2010-09-30

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谢谢bclz_vs
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liuyilin999 2010-09-29

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请问为什么 ArrayList.Sort(new Comparer)会自己去执行Compare(x, y)方法
并没有调用里面的方法Comparer.Compare(x, y)

边城的刀声 2010-09-29

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[Quote=引用 10 楼 liuyilin999 的回复:]

引用 8 楼 bclz_vs 的回复:
你这个叫显式接口实现，是为了隐藏接口中的成员用的，一般情况下不推荐使用显式接口实现

看来没有明白我的意思
ArrayList.Sort(new Comparer)是怎样执行Comparer类中方法的?并传入A,Y
[/Quote]



internal void QuickSort(int left, int right)

{

    do

    {

        int low = left;

        int hi = right;

        int median = Array.GetMedian(low, hi);

        this.SwapIfGreaterWithItems(low, median);

        this.SwapIfGreaterWithItems(low, hi);

        this.SwapIfGreaterWithItems(median, hi);

        object y = this.keys[median];

        do

        {

            try

            {

                while (this.comparer.Compare(this.keys[low], y) < 0)

                {

                    low++;

                }

                while (this.comparer.Compare(y, this.keys[hi]) < 0)

                {

                    hi--;

                }

            }

            catch (IndexOutOfRangeException)

            {

                throw new ArgumentException(Environment.GetResourceString("Arg_BogusIComparer", new object[] { y, y.GetType().Name, this.comparer }));

            }

            catch (Exception exception)

            {

                throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_IComparerFailed"), exception);

            }

            catch

            {

                throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_IComparerFailed"));

            }

            if (low > hi)

            {

                break;

            }

            if (low < hi)

            {

                object obj3 = this.keys[low];

                this.keys[low] = this.keys[hi];

                this.keys[hi] = obj3;

                if (this.items != null)

                {

                    object obj4 = this.items[low];

                    this.items[low] = this.items[hi];

                    this.items[hi] = obj4;

                }

            }

            low++;

            hi--;

        }

        while (low <= hi);

        if ((hi - left) <= (right - low))

        {

            if (left < hi)

            {

                this.QuickSort(left, hi);

            }

            left = low;

        }

        else

        {

            if (low < right)

            {

                this.QuickSort(low, right);

            }

            right = hi;

        }

    }

    while (left < right);

}