Executing a Statement Finally

The finally block is useful for cleaning up any resources allocated in the try block. Control is always passed to the finally block regardless of how the try block exits. This statement takes the following form:

try try-block finally finally-block

where:

try-block

Contains the code segment expected to raise the exception.

finally-block

Contains the exception handler and the cleanup code.

Remarks

Whereas catch is used to handle exceptions that occur in a statement block, finally is used to guarantee a statement block of code executes regardless of how the preceding try block is exited.

Example

In this example, there is one invalid conversion statement that causes an exception. When you run the program, you get a run-time error message, but the finally clause will still be executed and display the output.

// try-finally
using System;
public class TestTryFinally 
{
   public static void Main() 
   {
      int i = 123;
      string s = "Some string";
      object o = s;

      try 
      {
         // Invalid conversion; o contains a string not an int
         i = (int) o;   
      }

      finally 
      {
         Console.Write("i = {0}", i);
      }         
   }
}

Output

The following exception occurs:

System.InvalidCastException

Although an exception was caught, the output statement included in the finally block will still be executed, that is:

i = 123