//Func is a invokeable container for Mehod or function method
//that returns something. They can accept inputs based on the generals
//that you template on and reserve the last general template for the return.
//If you do not need a return or wish to return nothing check out the Action Class
//example:
Func<string/*Or some other type to return*/> YourFuncProperty
= new Func(()=>{/*do something*/ return "or return what you want";});
//or
Func<string/*Or some other type to return*/> YourFuncProperty
= ()=>{/*do something*/return "or return what you want";};
//for a paramiterized func
Func<int
/*Or some other types followed by others optional comma seperated*/,
string/*Or some other type to return last*/> YourParamitarizedFuncProperty =
(x/*Each Param will be to the comma seperated types*/)=>
{/*do some with the inputs*/return $"you entered a {x} or return what you want";};
// you can invloke them by calling their invokes.
string YouReturn = YourFuncProperty.Invoke();
string YouReturn = YourParamitarizedFuncProperty.Invoke(5);
//The last is the basic sycronous way. For a aysnc call uses
YourFuncProperty.BeginInvoke();
YourParamitarizedFuncProperty.BeginInvoke(5);
//however, you will need to begin a await with EndInvoke to get your result after.
string YouReturn = YourFuncProperty.EndInvoke();
string YouReturn = YourParamitarizedFuncProperty.EndInvoke(5);
//You can also fill them with defined methods in a class if you wish,
//but the signatures must match.
Func<string> YourActionDefinedProperty = YourDefinedMethod;
string YourDefinedMethod()
{
//do something
return "or return what you want";
}
//Example of use
public sealed class DataContainer
{
//A bit contrived but we will give the ablity to overide the printout
//of the class while still keeping it sealed. See the invoke at ToString.
//could be useful in a library or something?
static func<string> SealedFuncStringOverride;
DataContainer(datetime Date)
{
this.Date = Date;
}
public datetime Date {get; private set;}
public int Amount {get; private set;}
public string Info {get; private set;}
public string FirstName {get; private set;}
//The invoke is used in here.
public override string ToString()
{
if(SealedFuncStringOverride!=null)
return SealedFuncStringOverride.BeginInvoke();
return base.ToString;
}
}
// Func<T,TResult>
// example:
Func<int, string> foo = ConvertToString;
private string ConvertToString(int input) {
return input.ToString();
}
// or
private void Bar(Func<int, string> bar) {
Console.WriteLine(bar(myInt));
}
// In C#, this is how we define a function:
/*
In this case, the function is called 'myFunction', it takes
1 parameter which is an integer and doesn't return anything (void).
*/
static void myFunction(int a)
{
// INSERT CODE HERE
Console.WriteLine(a);
}
using System;
using System.Collections.Generic;
using static System.Console;
namespace CSFlow.Delegates.Others
{
public class ActionFunc
{
public static void Run ()
{
// Example of : Action
// Use action when a mathod return void
Action<string> display = new Action<string>(DisplayMessage);
display("Calculate Discount :");
// Example of : Func
// Use action when a mathod return value
Func<double, double> discount = new Func<double, double>(Discount);
display(discount(12.5).ToString());
List<Customer> custList = new List<Customer>();
custList.Add(new Customer { Id = 1, FirstName = "Joydip", LastName = "Kanjilal", State = "Telengana", City = "Hyderabad", Address = "Begumpet", Country = "India" });
custList.Add(new Customer { Id = 2, FirstName = "Steve", LastName = "Jones", State = "OA", City = "New York", Address = "Lake Avenue", Country = "US" });
custList.Add(new Customer { Id = 3, FirstName = "Sefat", LastName = "Anam", State = "OSA", City = "New York", Address = "Manhatten", Country = "US" });
// Example of : Predicate
// Use Predicate for search data
Predicate<Customer> FindAddress = customer => customer.Address == "Manhatten";
Customer searchData = custList.Find(FindAddress);
display($"{searchData?.FirstName} {searchData?.LastName} From - {searchData?.City} ");
ReadKey();
}
static void DisplayMessage (string message)
{
WriteLine(message);
}
static double Discount (double money)
{
return money * .5;
}
class Customer
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Address { get; set; }
public string City { get; set; }
public string State { get; set; }
public string Country { get; set; }
}
}
}