CODEWITHSUNDEEP
c#reflectiondelegates
Iulian Rosca
Iulian Rosca

Reputation: 1015

Passing delegate parameter to MethodInfo.Invoke

I have a window with multiple radio buttons : first group Sorting Algorithms and second directions (Ascending, Descending).

Every Sorting Method that I have contains :

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

and I mention that I need to keep this signatures (specially passing a delegate as a parameter).

Now the problem is , I have two methods
First one retrieves the selected algorithm 

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);
        }
    }

and the second one retrieves the direction : 

   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'.


something like this : 

        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);

Upvotes: 0

Views: 1167

Answers (1)

lavrik
lavrik

Reputation: 1474

Try 

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

Upvotes: 2

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