Re: How to pass information, classes between forms in Windows Application mode [ FINALLY!]

On Jul 23, 11:18 pm, "Jon Skeet [C# MVP]" <sk...@xxxxxxxxx> wrote:

That will generate CS0136. If you remove either of the local variable
declarations, it will compile. There will be warnings because we're
not actually *using* the variable, but it's only when there are
multiple local variable declarations that you see CS0136 - and that
would occur even without the instance variable existing at all.

Hope that helps,
Jon

Yes, it was very helpful. What I concluded is that there are
canonical ways of setting up a program (aka "good programming style",
or, "what has worked before") to compile and to run correctly with few
runtime errors, and these canonical ways should be followed if you
want to avoid making mistakes. I suspect the reason you don't get
more questions like mine is that people use canonical template
programs to build from, typically a working program from a cubicle
neighbor or fellow programmer.

Some things I got from this last post of yours:

**
this" will solve it to refer to variables, but if there's ambiguity
in the class names themselves, using the namespace is usually enough
to fix it. If it's still not (and there can be times where it's not
enough) you can use global::Namespace.Goes.Here.Classname

[that Namespace only gets rid of ambiguity in class names, rather than
ambiguity in instantiations of classes, aka 'variables', which is
handled by the 'this' pointer and/or by setting up your declarations/
code in the correct sequential order; I didn't know that about
Namespace]

**

and,

**
One hint: put a call to Console.ReadLine() at the end of your Main
method so you can see what's happened before the program terminates
[easier than stepping through the program line by line from the
debugger I suppose]

**
and,

**
MyDialogForm01 dlgForm = new MyDialogForm01();
//stuff deleted here
dlgForm = null; // at end of code; not strictly needed, apparently
some form of manual garbage collection


Avoid code like that. Setting a local variable to null at the end of
the method has no effect, and certainly doesn't trigger garbage
collection. In fact the object could have been collected before that
line of code, if nothing else references it.
(There are some situations involving captured variables where setting
a local variable to null *would* have an effect - probably an
unintended one - but that's a more complication situation. I mention
it only for completeness.)

[Shows me that even book examples are 'wrong' or bad style--since this
was from a book example]

**

and,

Yup. Using "this.myClass1" means "I want to refer to the instance
variable myClass1 belonging to "this" object, instead of a local
variable which happens to also have the name myClass1.

[which raises the question what happens when the this.variable also
happens to have a name that's the same with another variable outside
of the local variable? I hope the compiler would catch that, unless
there's another 'this.this.myClass1' you can use. On the other hand,
if you stick to 'good programming style' aka what I call 'canonical
form' programming, you will avoid using the same names unless you
specifically intend to hide/shadow a method/instance/variable, such as
in inheritance where you 'overide' or 'hide' a base class method in
the derived class.]

All in all, this thread reinforced my prejudice that you should stick
to canonical ways of building programs--learned through trial and
error--rather than understand, as you apparently have, the inner
workings of the C# language. Unless you plan to write a book on C#.

And I will buy your book, which I see as a C# Scott Meyers imitation,
whether you like it or not... :-)

I dare say I buy more programming books a year than most professional
programmers, who by and large are seat of the pants types that don't
learn too much theory outside of school. In fact, looking at most
posts here, it seems posters are interested in fixing their buggy code
than asking more fundamental questions, which I suspect some of the
more experienced posters here mistake for sophistication, LOL, but I
digress.

Cheers,

RL

.

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