Question

我有一个带有多个单选按钮的窗口：第一组排序算法和第二个方向（升序，降序）。

我所包含的每种排序方法：

 public delegate bool ComparatorDelegate(int a, int b);
 public static int[] sort(int[] array, ComparatorDelegate comparator){...}

我提到我需要保留这些签名（特别是将委托作为参数传递）。

现在的问题是，我有两种方法第一个检索所选算法

private Type getSelectedSortingMethod()
    {
        if (radioButtonBubbleSort.Checked)
        {
            return typeof(BubbleSort);
        }
        else if (radioButtonHeapSort.Checked)
        {
             return typeof(HeapSort);
        }
        else if (radioButtonQuickSort.Checked)
        {
             return typeof(QuickSort);
        }
        else
        {
             return typeof(SelectionSort);
        }
    }

，第二个检索方向：

   private Func<int, int, bool> getSelectedDirection()
    {
        Func<int, int, bool> selectedDirectionComparator = null;
        if (radioButtonAscending.Checked)
        {
            selectedDirectionComparator = ComparatorUtil.Ascending;
        }
        else if (radioButtonDescending.Checked)
        {
            selectedDirectionComparator = ComparatorUtil.Descending;
        }
        return selectedDirectionComparator;
    }

Question : How can I invoke the sort method with a delegate parameter , because passing Func throws exception ?

Exception :
Object of type 'System.Func`3[System.Int32,System.Int32,System.Boolean]' cannot be converted to type 'Lab2.SortingMethods.HeapSort+ComparatorDelegate'.

像这样的东西：

        Type sortingMethodClass = getSelectedSortingMethod();
        MethodInfo sortMethod = sortingMethodClass.GetMethod("sort");
        Func<int, int, bool> selectedDirectionComparator = getSelectedDirection();
        int[] numbersToSort = getValidNumbers();
        Object[] parameters = new Object[] {numbersToSort,selectedDirectionComparator};
        sortMethod.Invoke(null, parameters);
        displayNumbers(numbersToSort);

Answer 1

尝试

 Object[] parameters = new Object[] 
   { numbersToSort, new ComparatorDelegate (selectedDirectionComparator)};

将委托参数传递给MethodInfo.Invoke

1 个答案: