How to catch multiple exceptions at once in C#

In C#, we manage exception handling using the try-catch block. Multiple exceptions can be caught separately or at once, depending on the developer's choice.

In this shot, we'll see how to catch multiple exceptions at once.

Catching multiple exceptions at once using when

In this approach, we catch all the exceptions inside a single catch block using the when keyword.

Example

using System;
class HelloWorld
{
    static void Main()
    {
        try {
          // throwing a divide by zero exception
          throw new DivideByZeroException();
        } 
        // catching multiple exceptions at once using 'when'
        catch (Exception e) when (
          e is NullReferenceException ||
          e is DivideByZeroException ||
          e is IndexOutOfRangeException
        ) {
          Console.WriteLine("Exception occured");
        }
    }
}

Explanation

In the code snippet above, inside the main function:

  • Lines 7–10: We create a try block.
  • Line 9: We deliberately throw a DivideByZeroException.
  • Lines 12–18: We catch multiple exceptions at once using when and separate each caught exception by an || (OR) operator.

Catching multiple exceptions at once using switch-case

In this approach, we catch all the exceptions inside a single catch block using the switch-case statement.

Example

using System;
class HelloWorld
{
    static void Main()
    {
        try {
          // throwing a divide by zero exception
          throw new DivideByZeroException();
        } 
        // catching multiple exceptions at once using 'switch case'
        catch (Exception e) {
          switch (e.GetType().ToString()) {
            case "System.NullReferenceException":
              Console.WriteLine("NullReferenceException occured");
              break;
            case "System.DivideByZeroException":
              Console.WriteLine("DivideByZeroException occured");
              break;
            case "System.IndexOutOfRangeException":
              Console.WriteLine("IndexOutOfRangeException occured");
              break;
            default:
              Console.WriteLine("Exception occured");
              break;
          }
        }
    }
}

Explanation

In the code snippet above, inside the main function:

  • Lines 7–10: We create a try block.
  • Line 9: We deliberately throw a DivideByZeroException.
  • Lines 12–27: We catch multiple exceptions at once using the switch-case statement. We first get the type of exception using GetType(), convert it to a string using ToString(), and then pass it to the switch() function. We list all the exceptions that are caught using the case statement.

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