Question

Suppose I have a class DisposableObject which implements IDisposable. There is a risk it can throw an exception from any constructor and from the DoStuff function. I want to do something like this, so that no matter what happens, the object is disposed properly:

edit: I would like to avoid duplicate code, so a using inside each if/else block is not desirable (the code is a lot more complex than here)

edit2: Yes the try/finally error was wrong, changed it to use of unassigned local variable.

using (DisposableObject worker)
{
    if(/*condition*/)
        worker = new DisposableObject(/*args*/)
    else
        worker = new DisposableObject(/*other args*/)
    worker.DoStuff();
}

But I can’t, because the compiler says I must provide an initializer in the using statement.
I can’t use try/finally either:

DisposableObject worker;
try
{
    if(/*condition*/)
        worker = new DisposableObject(/*args*/)
    else
        worker = new DisposableObject(/*other args*/)
    worker.DoStuff();
}
finally
{
    worker.Dispose();
}

The compiler says use of unassigned local variable ‘worker’.

So what can I do? Obviously I can’t simply go like this…

DisposableObject worker;
if (/*condition*/)
    worker = new DisposableObject(/*args*/)
else
    worker = new DisposableObject(/*other args*/)
worker.DoStuff();
worker.Dispose();

Because I can’t be sure the Dispose() function is ever reached.

Answer 1

Actually, the compiler says that you are using a potentially uninitialized variable, so just initialize it:

DisposableObject worker = null;
try
{
    if(/*condition*/)
        worker = new DisposableObject(/*args*/)
    else
        worker = new DisposableObject(/*other args*/)
    worker.DoStuff();
}
finally
{
    if(worker != null)
        worker.Dispose();
}