In c#, the throw is a keyword and it is useful to throw an exception manually during the execution of the program and we can handle those thrown exceptions using try−catch blocks based on our requirements.
By using throw keyword in the catch block, we can re-throw an exception that is handled in the catch block. The re-throwing an exception is useful when we want to pass an exception to the caller to handle it in a way they want.
Following is the example of re−throwing an exception to the caller using throw keyword with try-catch blocks in c#.
class Program{ static void Main(string[] args){ try{ Method2(); } catch (System.Exception ex){ System.Console.WriteLine($"{ex.StackTrace.ToString()} {ex.Message}"); } Console.ReadLine(); } static void Method2(){ try{ Method1(); } catch (System.Exception){ throw; } } static void Method1(){ try{ throw new NullReferenceException("Null Exception error"); } catch (System.Exception){ throw; } } }
This is how we can re-throw an exception to the caller using throw keyword in catch block based on our requirements.
at DemoApplication.Program.Method1() in C:\Users\Koushik\Desktop\Questions\ConsoleApp\Program.cs:line 49 at DemoApplication.Program.Method2() in C:\Users\Koushik\Desktop\Questions\ConsoleApp\Program.cs:line 37 at DemoApplication.Program.Main(String[] args) in C:\Users\Koushik\Desktop\Questions\ConsoleApp\Program.cs:line 24 Null Exception error