Question

Is there a way for me to make a function call on a new instance of a variable without first declaring it?

So for example in Java you could do:

new foo().bar(parameters);

I’ve tried something similar in Visual Basic, but it’s a syntax error. For the moment I’m creating a variable and then running the function.

dim instance as new foo()
instance.bar(parameters)

Is there something I can do similarly to the Java code above?

Answer 1

Not exactly. You can do so in a larger expression by surrounding the instantiation in parenthesis, for instance:

MessageBox.Show((New String("y"c, 1)).ToUpper())

Or, in fact, while I find it more confusing, you don’t actually even need the parenthesis around the instantiation:

MessageBox.Show(New String("y"c, 1).ToUpper())

However, if you want to just call a method like that, the only way I know of is to wrap in in a CType operator. For instance, if you had a class like this:

Private Class Test
    Public Sub Show()
        MessageBox.Show("Hello")
    End Sub
End Class

You could call the Show method like this:

CType(New Test(), Test).Show()

But, it is a bit clumsy.

Actually, SSS provided an even better answer since I posted this yesterday. Instead of wrapping it in a CType operator, you can use the Call keyword. For instance:

Call New Test().Show()