C# Web Service - Return then Finally - What happens first

Question

In C#.NET, let's take the following example

[WebMethod]
public int TakeAction()
{
    try {
        //Call method A
        Return 1;
    } catch (Exception e) {
        //Call method B
        Return 0;
    } finally {
        //Call method C
    }
}

Now let's say method C is a long running process.

Does the client who invokes TakeAction get back the return value, before method C is invoked, or after it is invoked / completed?

Answer 1

The return value is evaluated first, then the finally block executes, then control is passed back to the caller (with the return value). This ordering is important if the expression for the return value would be changed by the finally block. For example:

Console.WriteLine(Foo()); // This prints 10

...

static int Foo()
{
    int x = 10;
    try
    {
        return x;
    }
    finally
    {
        // This executes, but doesn't change the return value
        x = 20;
        // This executes before 10 is written to the console
        // by the caller.
        Console.WriteLine("Before Foo returns");
    }
}