Try Catch

During program execution an error can be thrown. Instead of ending the program an error can be caught and a certain code can be executed.

Error Handling

Syntax for handling error:

try { // code that may throw exception. } catch (ExceptionType exceptionName) { // handling the error }

Let's look at the following example:

using System; namespace ConsoleApp1 { class Program { static void Main(string[] args) { try { Console.WriteLine("Executing try block code."); throw new Exception("My error message."); } catch (Exception ex) { Console.WriteLine("Catching an error: "); Console.WriteLine(ex.Message); } } } }

Output:

Executing try block code. Catching an error: My error message.

Since an error is thrown in the try block, the code from the catch block is called.

Classes and Error Handling

An error can be thrown when a validation fails in setter.

Example:

using System; namespace ConsoleApp1 { class Person { public string name { get; set; } public int age { get { return age; } set { if (value < 0) { throw new Exception("Age cannot be less than zero."); } age = value; } } public Person(string usernameValue, int ageValue) { this.name = usernameValue; this.age = ageValue; } } class Program { static void Main(string[] args) { try { Person personObj = new Person("Alex", -1); } catch (Exception ex) { Console.WriteLine("Object creation failed: "); Console.WriteLine(ex.Message); } } } }

Output:

Object creation failed: Age cannot be less than zero.

At line 38 a negative number (-1) is passed for age of the person object. This causes an error to be throw (due to line 18).