List of All New Features in C# 6.0: Part 1

5. Exception filters

Exception filters are a new concept for C#. In C# 6.0 they are already supported by the VB compiler but now they are coming into C#. Exception filters allow us to specify a condition with a catch block so if the condition will return true then the catch block is executed only if the condition is satisfied. This is also the best attribute of new C# 6.0 that makes it easy to do exception filtrations in also that type of code contains a large amount of source code. Let's have an example.

Code

1. using System;
2. using System.Collections.Generic;
3. using System.Linq;
4. using System.Text;
5. using System.Threading.Tasks;
6. using System.Console;
7. namespace project5
8. {
9. class Program
10. {
11. static void Main(string[] args)
12. {
13. int val1 = 0;
14. int val2 = 0;
15. try
16. {
17. WriteLine("Enter first value :");
18. val1 = int.Parse(ReadLine());
19. WriteLine("Enter Next value :");
20. val2 = int.Parse(ReadLine());
21. WriteLine("Div : {0}", (val1 / val2));
22. }
23. catch (Exception ex) if (val2 == 0)
24. {
25. WriteLine("Can't be Division by zero ☺");
26. }
27. catch (Exception ex)
28. {
29. WriteLine(ex.Message);
30. }
31. ReadLine();
32. }
33. }
34. }
Output

If all the values are entered by user id correctly then the output will be:



If the user enters an invalid value for division, like 0, then it will throw the exception that will be handled by Exception filtration where you mentioned an if() with catch{} block and the output will be something.

6. Await in catch and finally block

This is a new behavior of C# 6.0 that now we are able to call async methods from catch and also from finally. Using async methods are very useful because we can call then asynchronously and while working with async and await, you may have experienced that you want to put some of the result awaiting either in a catch or finally block or in both. Let's suppose we need to call an async method and there is a try and a catch{} block so when the exception occurs it is thrown in the catch{} block. We need to write log information into a file or send a service call to send exception details to the server so call the asynchronous method, so use await in catch{}, this is only possible in C# 6.0. Let's have an example.

We have a class and there is a method that is async and we need to call this with two parameters and if there is an exception then that will we return an exception and will go to the catch{} block and then we will call an async method using await and finally we have called the same in the finally.

Call the async div() in Main().



Code

1. using System;
2. using System.Collections.Generic;
3. using System.Linq;
4. using System.Text;
5. using System.Threading.Tasks;
6. using System.Console;
7. namespace project6
8. {
9. class Program
10. {
11. static void Main(string[] args)
12. {
13. MyMath obj = new MyMath();
14. obj.Div(12, 0);
15. ReadLine();
16. }
17. }
18. public class MyMath
19. {
20. public async void Div(int value1, int value2)
21. {
22. try
23. {
24. int res = value1 / value2;
25. WriteLine("Div : {0}", res);
26. }
27. catch (Exception ex)
28. {
29. await asyncMethodForCatch();
30. }
31. finally
32. {
33. await asyncMethodForFinally();
34. }
35. }
36. private async Task asyncMethodForFinally()
37. {
38. WriteLine("Method from async finally Method !!");
39. }
41. private async Task asyncMethodForCatch()
42. {
43. WriteLine("Method from async Catch Method !!");
44. }
45. }
46. }
Output

If there is no exception then:



And when the exception occurs:

7. Null-Conditional Operator

The Null-Conditional operator is a new concept in C# 6.0 that is very beneficial for a developer in a source code file that we want to compare an object or a reference data type with null. So we need to write multiple lines of code to compare the objects in previous versions of C# 5.0 but in C# 6.0 we can write an in-line null-conditional with the ? and ?? operators, so let's have an example and compare both versions, C# 5.0 vs C# 6.0. We will write the code for both version.

Let's suppose we have two classes:



Now we need to write the code to compare the objects of the employee class with null in C# 5.0. So we need to write if() and else multiple lines.



If we want to write the same code in C# 6.0 then we can use ? and ?? to check the null value of an object, as in the following:

Condition ? code that use in case not null ?? in case of null



Output

The output when no object is null:



The output when an object is null:



Code


1. using System;
2. using System.Collections.Generic;
3. using System.Linq;
4. using System.Text;
5. using System.Threading.Tasks;
6. using System.Console;
7. namespace project7
8. {
9. class Program
10. {
11. static void Main()
12. {
13. Employee emp = new Employee();
14. emp.Name = "Nitin Pandit";
15. emp.EmployeeAddress = new Address()
16. {
17. HomeAddress = "Noida Sec 15",
18. OfficeAddress = "Noida Sec 16"
19. };
20. WriteLine((emp?.Name) + " " + (emp?.EmployeeAddress?.HomeAddress??"No Address"));
21. ReadLine();
22. }
23. }
24. class Employee
25. {
26. public string Name { get; set; }
27. public Address EmployeeAddress { get; set; }
28. }
29. class Address
30. {
31. public string HomeAddress { get; set; }
32. public string OfficeAddress { get; set; }
33. }
34. }

8. Expression–Bodied Methods

An Expression–Bodied Method is a very useful way to write a function in a new way and also very useful for those methods that can return their value by a single line so we can write those methods by using the “=>“ lamda Operator in C# 6.0 so let's have an example.

We will just write a method in both versions of C# 5.0 vs C# 6.0 with a method that only returns a message of a string value.

In C# 5.0:



In C# 6.0



Output

The output will be the same in both.



Code

1. using System;
2. using System.Collections.Generic;
3. using System.Linq;
4. using System.Text;
5. using System.Threading.Tasks;
6. using System.Console;
7. namespace Project8
8. {
9. class Program
10. {
11. static void Main(string[] args)
12. {
13. WriteLine(GetTime());
14. ReadLine();
15. }
16. public static string GetTime()=> "Current Time - " + DateTime.Now.ToString("hh:mm:ss");
18. }
19. }

9. Easily format strings using String interpolation

To easily format a string value in C# 6.0 without any string.Format() method we can write a format for a string. It's a very useful and time consuming process to define multiple string values by “\{ variable }”. So let's have an example on String interpolation. First we are writing the source code by string.Format().

Now by “\{variable}”.



Output

The output will be the same in both but by “\{variable}” is a very short way to write the same code.



Code


1. using System;
2. using System.Collections.Generic;
3. using System.Linq;
4. using System.Text;
5. using System.Threading.Tasks;
6. using System.Console;
7. namespace Project9
8. {
9. class Program
10. {
11. static void Main()
12. {
13. string FirstName = "Nitin";
14. string LastName = "Pandit";
16. // With String Interpolation in C# 6.0
17. string output= "\{FirstName}-\{LastName}";
18. WriteLine(output);
19. ReadLine();
20. }
21. }
22. }

Thank you for reading this article.

Next article - List of All New Features in C# 6.0: Part 2