Passing around member functions in C# -
mostly comes handy c# delegates store object member function. there way, store -- , pass parameters -- member function itself, old pointer-to-member-function in c++?
in case description less clear, give self-contained example. and, yes, in example insistence pass around member functions totally pointless, have more serious uses this.
class foo { public int { get; set; } /* can done? public static int apply (foo obj, ???? method, int j) { return obj.method (j); } */ public static int applyhack (foo obj, func<int, int> method, int j) { return (int) method.method.invoke (obj, new object [] { j }); } public static readonly foo _ = new foo (); // dummy object applyhack public int multiply (int j) { return * j; } public int add (int j) { return + j; } } class program { static void main (string [] args) { var foo = new foo { = 7 }; console.write ("{0}\n", foo.applyhack (foo, foo._.multiply, 5)); console.write ("{0}\n", foo.applyhack (foo, foo._.add, 5)); console.readkey (); } } you see, workaround i've found rather ugly , slow.
taking existing code:
public static int applyhack (foo obj, func<int, int> method, int j) { return (int) method.method.invoke (obj, new object [] { j }); } you this:
public static int applyhack (foo obj, func<int, int> method, int j) { var func = (func<int,int>)delegate.createdelegate(typeof(func<int,int>), obj, method.method); return func(j); } this create new delegate around method , new object. take first example:
public static int apply (foo obj, ???? method, int j) { return obj.method (j); } the type looking system.reflection.methodinfo , this:
public static int apply (foo obj, methodinfo method, int j) { var func = (func<int,int>)delegate.createdelegate(typeof(func<int,int>), obj, method); return func(i); } note while allocating delegates each invocation, believe still faster using reflection, since not have box function input/output, nor store in object[] arrays.
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