Cast from a delegate to a func

I have a project in school where my teacher is asking us to add a delegate to a List of Funcs. The code I have below is having issues in the AddDel method. Intellisense is telling me that it can't convert from the Delegate into a Func but my teacher insists that it should totally do that without a problem. What am I doing wrong? 

public class TestDelegate
{
    private delegate string MyDel(int iVal, double dVal, char cVal, string sVal);
    private List<Func<int, double, char, string, string>> _DList;
    public TestDelegate() { }       
    public void AddDel()
    {            
        //Creating a delegate
        MyDel myDel = new MyDel(MyFunction);
        _DList.Add(myDel); //Adding it to the TestDelegate
    }
    public void RunTests()
    {
        int idata = 1;
        double ddata = 5.1;
        char cdata = 'A';
        string sdata = "Method";
        foreach (Func<int, double, char, string, string> myDel in _DList)
            WriteLine(myDel(idata, ddata++, cdata++, sdata + idata++));
    }
    private static string MyFunction(int iVal, double dVal, char cVal, string sVal)
    {
        return $"{sVal}:\t{iVal} {dVal}{cVal}";
    }
}
Jon Skeet
people
quotationmark

Basically, you shouldn't declare your own delegate here at all. There are no conversions between delegate types like this.

You want a Func<int, double, char, string, string>, so declare one:

Func<int, double, char, string, string> func = MyFunction;
_DList.Add(func);

Or more simply, just call Add:

_DList.Add(MyFunction);

If you really want to keep your current code, you can create a Func<...> that wraps your delegate:

MyDel myDel = new MyDel(MyFunction);
var func = new Func<int, double, char, string, string>(myDel);
_DList.Add(func); //Adding it to the TestDelegate

... but I don't actually see any benefit from that here.

people

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