合并排序错误不包含定义，也不包含扩展方法

Question

我试图从program.cs调用类Merge Sort但是错误一直显示项目不包含'Merge Sort'的定义，并且没有扩展方法'Merge Sort'接受类型的第一个参数可以找到'projectname.MergeSort'。下面是我对2个类的代码。任何人都可以帮忙吗？感谢

类合并排序代码：

class MergeSort
{
    static public void MergeSorting(int[] array, int left, int mid, int right)
    {
        int[] temp = new int[25];
        int i, left_end, num_elements, tmp_pos;

        left_end = (mid - 1);
        tmp_pos = left;
        num_elements = (right - left + 1);

        while ((left <= left_end) && (mid <= right))
        {
            if (array[left] <= array[mid])
                temp[tmp_pos++] = array[left++];
            else
                temp[tmp_pos++] = array[mid++];
        }

        while (left <= left_end)
            temp[tmp_pos++] = array[left++];

        while (mid <= right)
            temp[tmp_pos++] = array[mid++];

        for (i = 0; i < num_elements; i++)
        {
            array[right] = temp[right];
            right--;
        }
    }

    static public void MergeSort_Recursive(int[] array, int left, int right)
    {
        int mid;

        if (right > left)
        {
            //splitting array into 2
            mid = (right + left) / 2;
            MergeSort_Recursive(array, left, mid);
            MergeSort_Recursive(array, (mid + 1), right);

            MergeSorting(array, left, (mid + 1), right);
        }
    }
}

类program.cs代码：

//array to be sorted
        int[] array = { 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 };

        //sort the array using merge sort
        MergeSort mSort = new MergeSort();
        int[] mergeSortedArray = mSort.MergeSort(array);