How does the try catch finally block work?

Question

In C#, how does a try catch finally block work?

So if there is an exception, I know that it will jump to the catch block and then jump to the finally block.

Answer 1

Yes the finally clause gets exeucuted if there is no exception. Taking an example

     try
        {
            int a = 10;
            int b = 20;
            int z = a + b;
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }
        finally
        {
            Console.WriteLine("Executed");
        }

So here if suppose an exception occurs also the finally gets executed.

Answer 2

Yes, the finally block gets run whether there is an exception or not.

Try
    [ tryStatements ]
    [ Exit Try ]
[ Catch [ exception [ As type ] ] [ When expression ]
    [ catchStatements ]
    [ Exit Try ] ]
[ Catch ... ]
[ Finally
    [ finallyStatements ] ] --RUN ALWAYS
End Try

See: http://msdn.microsoft.com/en-us/library/fk6t46tz%28v=vs.80%29.aspx

Answer 3

Yes, Finally will always execute.

Even if there is no catch block after try, finally block will still execute.

Basically finally can be used to release resources such as a file streams, database connections and graphics handlers without waiting for the garbage collector in the runtime to finalize the object.

       try
        {
            int a = 10;
            int b = 0;
            int x = a / b;
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
        }
        finally
        {
            Console.WriteLine("Finally block is executed");
        }
        Console.WriteLine("Some more code here");

Output:

System.DivideByZeroException: Attempted to divide by zero.

Finally block is executed

Rest of the code

Source : Exception handling in C# (With try-catch-finally block details)

Answer 4

finally block always run , no matter what. just try this method

     public int TryCatchFinally(int a, int b)
    {
        try
        {
            int sum = a + b;
            if (a > b)
            {
                throw new Exception();
            }
            else
            {
                int rightreturn = 2;
                return rightreturn;
            }
        }
        catch (Exception)
        {
            int ret = 1;
            return ret;
        }
        finally
        {
            int fin = 5;
        }
    }

Answer 5

        try
        {
            //Function to Perform
        }
        catch (Exception e)
        {
         //You can display what error occured in Try block, with exact technical spec (DivideByZeroException)
            throw; 
            // Displaying error through signal to Machine, 
            //throw is usefull , if you calling a method with try from derived class.. So the method will directly get the signal                
        }

        finally  //Optional
        {
            //Here You can write any code to be executed after error occured in Try block
            Console.WriteLine("Completed");
        }

Answer 6

The finally block will always execute before the method returns.

Try running the code below, you'll notice where the Console.WriteLine("executed") of within the finally statement, executes before the Console.WriteLine(RunTry()) has a chance to execute.

static void Main(string[] args)
{
    Console.WriteLine("Hello World!");
    Console.WriteLine(RunTry());
    Console.ReadLine();
}
public static int RunTry()
{
    try
    {
        throw new Exception();
    }
    catch (Exception)
    {
        return 0;
    }
    finally
    {
        Console.WriteLine("executed");
    }
    Console.WriteLine("will not be executed since the method already returned");
}

See the result: