What are user-defined exceptions in C#?

Like any other programming language, in C#, you can easily create a user-defined exception. User-defined exception classes are derived from the Exception class. Custom exceptions are what we call user-defined exceptions.

In the below example, the exception created is not a built-in exception; it is a custom exception −

TempIsZeroException

You can try to run the following code to learn how to create a user-defined exception in C# −

Example

 Live Demo

using System; namespace Demo {    class TestTemperature {       static void Main(string[] args) {          Temperature temp = new Temperature();          try {             temp.showTemp();          } catch(TempIsZeroException e) {             Console.WriteLine("TempIsZeroException: {0}", e.Message);          }          Console.ReadKey();       }    } } public class TempIsZeroException: Exception {    public TempIsZeroException(string message): base(message) {    } } public class Temperature {    int temperature = 0;    public void showTemp() {       if(temperature == 0) {          throw (new TempIsZeroException("Zero Temperature found"));       } else {          Console.WriteLine("Temperature: {0}", temperature);       }    } }

Output

TempIsZeroException: Zero Temperature found