Why callback error in C #?

Error while executing this code, displays on linux

Test begin... TestFunction, i = 0!!! 

Code:

 using System; namespace Callback { public class TestCallbacks { public Action<int, bool, decimal, decimal, bool> TestCallback; } public static class TestClass { public static TestCallbacks Callbacks; public static void Initialize(TestCallbacks callbacks) { Callbacks = callbacks; } public static void TestCallback() { // Passing i = 100! Callbacks.TestCallback(100, true, 200m, 300m, false); } } class Program { private static void TestFunction(int i, bool b1, decimal d1, decimal d2, bool b2) { Console.WriteLine($"TestFunction, i = {i}!!!"); } static void Main(string[] args) { Console.WriteLine("Test begin..."); var testCallbacks = new TestCallbacks() { TestCallback = TestFunction }; TestClass.Initialize(testCallbacks); TestClass.TestCallback(); } } }