C# Discussion Boards - CodeProject

MarkRHolbrook wrote:
Used the graphics page of the apple II as a buffer. Watching programs come in was sort of physadellic as it write binary data to the graphics page

Reminds me of the graphics machines at school. They were 64K Z-80 systems running CP/M. The lower 48K was bank-switched with the display buffer, so you had to call a routine 'up high' to draw a graphics primitive. It would switch the program memory out and display bank in, draw the point/line/whatever, and then switch the program memory back in. Occasionally the bank switch didn't work properly, and you would end up watching your program on the screen.

Kind of nifty, especially when you'd been in the lab for 40 hours straight subsisting on vending machine coffee and three packs of cigarrettes.

Software Zen: delete this;

Hi Mark, you are a true "veteran," a true example of technical "ontology recapitulates hardware phylogeny" Smile | :)

I really enjoyed following the course of your pilgrimage in the digital realm. My first computer circa 1981 was a little Radio Shack Color Computer, on which I taught myself 6809 assembly language, and, of cours, Basic. My second computer was a Mac that some very young Jamaican guy in Berkeley, who was a genius with hardware, had got from some bootlegger of rejects Apple intended to go to a recycler, or to be destroyed. Robert fixed it up, and when I bought it, for about US $600 around 1984, it had a Spanish keyboard, and all the second row keys from the bottom were somehow shifted right one character: so that when you typed an "m" you got a comma Smile | :)

thanks, for the memories,

bill

Google CEO, Erich Schmidt: "I keep asking for a product called Serendipity. This product would have access to everything ever written or recorded, know everything the user ever worked on and saved to his or her personal hard drive, and know a whole lot about the user's tastes, friends and predilections." 2004, USA Today interview

Many of us here have been "around". I've read your stories and love every one. It's hard to be 56, have all this experience and my current "director" of software development is about 30. He's a great guy, extremely knowledgable and good at what he does but he lacks the experience people like you and I have had. Doesn't make him a bad person. We all start somewhere. He just has a blank stare on his face when I talk about 300 baud modems. LOL.

Hi Gary, I am sure our souls are equally eternal, even if I do have more years on the meat-package than you. My career in software was, in the context of the "big picture" of my life, a strange diversion that unfolded by the principles of serendipity's quantum mechanics (and lots of hard work).

People who had known me before my first career, in social work, psychotherapy, and academic social science, were quite astounded that a former mad-poet, and ersatz yogi, from the 1960's cultural topsy-turvy maelstrom ever made it to back to Earth in his thirties, let alone made it into university level academia. They were even more shocked when they heard, I had been published by Addison-Wesley by age 44, and later, I worked at Adobe, at age forty-five, and they saw my name in the about-box of Adobe Illustrator 3.2, and 5.0, or heard I was one of three people who created the proof-of-concept prototype that, later, became Acrobat (under the keen eye, and subtle guidance, of John Warnock, the greatest technical mind I've ever had the privilege of working directly with).

My "true love" is literature, and writing poetry, and fiction, and I'm delighted that about age fifty-one I "re-designed" my life, and moved to Asia, and returned to the worship of the Muses. But, I still enjoy the hell out of programming, still occasionally program, or do web-related stuff, or graphic design, for $, so I have not deserted the shrine of the Goddess Techne.

Along the way: wives (virtual, and legal): six. Children: zero. Ex-wives (legal): two.

Life is as good as I allow it to be !

bill

Google CEO, Erich Schmidt: "I keep asking for a product called Serendipity. This product would have access to everything ever written or recorded, know everything the user ever worked on and saved to his or her personal hard drive, and know a whole lot about the user's tastes, friends and predilections." 2004, USA Today interview

Just to clarify:

C#

static bool notAvailableOutsideFormClassScope = true;

is in fact NOT private. Neither is it public. The default is internal (scope=assembly). As a default this makes the most sense in my opinion (regardless if having a default makes sense at all)

I still specify the visibility for every class (and member). Just because I don't like relying on defaults Wink | ;)

Edit:
See Access Modifiers (C# Programming Guide) (MSDN)[^] First paragraph of the section "Class and Struct Accessibility"

Edit2:
Regarding Resharper (At least in Version 6.1) you let Resharper suggest explicit access modifiers: Smile | :)

-> Resharper -> Options... -> Code Editing -> Formatting Style -> Other -> Modifiers -> "Use explicit private modifier" / "Use explicit internal modifier"

modified 5-Sep-13 9:35am.

Hi Nicholas, that's a very interesting, and appreciated, response, thanks.

I am definitely a devotee of the cult whose mantra is: "declared accessibility keeps you virgin."

I studied the MSDN page you kindly sent me a link to: the word 'static does not appear in it; the distinction between 'private and 'internal mentioned there applies to classes, and structs: "Classes and structs that are declared directly within a namespace (in other words, that are not nested within other classes or structs) can be either public or internal. Internal is the default if no access modifier is specified." The example I showed uses variables. But, I did find that page worth studying, and bookmarking, for future reference !

Given these two declarations in a Form class' scope:

static bool notAvailableOutsideFormClassScope1 = true;
private static bool notAvailableOutsideFormClassScope2 = true;

There is no difference in accessibility/behavior outside/inside the Form class' scope.

I've actually gone to the trouble, just to make sure, of testing (code on request) if there's any difference in accessibility/behavior.

In externally declared classes, one static, the other public, neither the static class, or the public class, can access those static bool, form class' scoped, variables. As you would expect, both the static class, and an instance of the public class created in the Form's scope, where those variables are declared, can use/access (set, get) those variables.

So, I see no evidence for your assertion that a static variable declared without access-modifier is, by default, 'internal, and not 'private.

ReSharper 8: Resharper/Options/Code Editing/C#/Formatting Style/Other/Modifiers dialog ... I note that I have both options, "Use explicit internal modifier," and "Use explicit private modifier:" enabled.

The default behavior in ReSharper 8, with these options enabled, is to prepend the 'private access-modifier for a static variable, after you type it.

bill

Google CEO, Erich Schmidt: "I keep asking for a product called Serendipity. This product would have access to everything ever written or recorded, know everything the user ever worked on and saved to his or her personal hard drive, and know a whole lot about the user's tastes, friends and predilections." 2004, USA Today interview

modified 6-Sep-13 1:29am.

Hm... Very interesting Bill Thumbs Up | :thumbsup:

Had to test it myself too now Smile | :)

It looks like the default access modifier is only internal for classes and structs, while it is private for class members (Variables, Methods, etc.). So I was wrong in the first place Blush | :O

(considering the topic/examples were about variables). Looks like a lack of consistency to me. A reason more for me to dislike those defaults Wink | ;)

I've never noticed that as I always write the access modifier to be clear of my intentions.

As far as I can see, the default value should be sufficient in most cases to be able to use your class without any explicit modifiers. private makes usually no sense for a class (as you won't be able to use it anywhere except the top level class "possessing this class) and internalallows enough for usage in you application. if you want to expose it more you can still change it to public. A default of private for class members also seems reasonable given that you usually want fields to private (and probably a bunch of class methods too).

BillWoodruff wrote:
The default behavior in ReSharper 8, with these options enabled, is to prepend the 'private access-modifier for a static variable, after you type it.

You should also be able to change the order of the modifiers on the following line Smile | :)

Hi Nicholas,

I am curious now: in what circumstances have you ever used a static class, struct, or fields, or method, defined in the scope of a Form's class, and either made it private by declaring it private, or let it become private by default when you left off the access-modifier ?

I have never found a reason to do that, myself, but I suspect there are reasons for doing it under some circumstances that I'm not aware of ... and, I'd like to be aware of what possible use a private static something-or-other could be !

fyi: I went into ReSharper 8, and changed the modifier list so 'internal was at the top of the list. Declaring a static boolean variable in a Form: ReSharper 8 prepended the 'private access-modifier as soon as I completed the declaration.

It is good to learn new things, and it is good to have cause to question what one takes for granted, so I thank you for motivating me to revisit these aspects of .NET Smile | :)

yours, Bill

Google CEO, Erich Schmidt: "I keep asking for a product called Serendipity. This product would have access to everything ever written or recorded, know everything the user ever worked on and saved to his or her personal hard drive, and know a whole lot about the user's tastes, friends and predilections." 2004, USA Today interview

Hey Bill

BillWoodruff wrote:
I am curious now: in what circumstances have you ever used a static class, struct, or fields, or method, defined in the scope of a Form's class, and either made it private by declaring it private, or let it become private by default when you left off the access-modifier ?

There are things where it makes sense to declare something as private static. And I guess if you let it default let it become private or you explicitly declare it as private is just a preference... Where mine is to explicitly tell me and everyone else which visibility I am aiming for (private, internal, protected or public).

In our code the tracer for Log4net is declared as such. Because you want to be able to log in both static and non-static methods through it, but you don't want any other class to log through that same logger.

So in this case: The tracer instance of the form is declared as private static. So you're able to use the tracer in methods of the form to log information. Sure, as long as you don't need static methods in the form class you could also declare it without the static modifier. However the tracer is declared in every class in the same manner so why bother to change it and change it back when you happen to use the instance in a static method?

I don't know about other usages for such a thing on top of my head but I guess there might be some Wink | ;)

BillWoodruff wrote:
fyi: I went into ReSharper 8, and changed the modifier list so 'internal was at the top of the list. Declaring a static boolean variable in a Form: ReSharper 8 prepended the 'private access-modifier as soon as I completed the declaration.

Yeah, there are a lot of options for Resharper. But I like it because I don't have to think about formatting my code Poke tongue | ;-P

yours, Nicholas

Well if all you're writing is front-end stuff, then you wouldn't have many public members anyway. I write mostly back-end library stuff so a great many of my members are public static methods, but not many fields.

A few examples:

public static readonly System.Type BaseType = typeof(T) ;
public static readonly Rational MaxValue = new Rational ( decimal.MaxValue , 1M ) ;
public static event ErrorDelegate OnError ;
public static ValueOf<T> operator + ( ValueOf<T> Op1 , ValueOf<T> Op2 ) ...
public static System.Reflection.PropertyInfo CommandTextAttributeProperty { get ; private set ; }

Consistency allowed me to find these easily.

i suggest frist one style.

I always like to use the access modifier first.

I'm with Richard Deeming here, I use the first method myself. As Richard said, consistency is the key!

public static is more poetic. We've been using it for a decade now. Why change it? Blush | :O

Starting to think people post kid pics in their profiles because that was the last time they were cute - Jeremy.

Vunic wrote:
public static is more poetic.

Just curious: is private static any less poetic ?

bill

Google CEO, Erich Schmidt: "I keep asking for a product called Serendipity. This product would have access to everything ever written or recorded, know everything the user ever worked on and saved to his or her personal hard drive, and know a whole lot about the user's tastes, friends and predilections." 2004, USA Today interview

Private static is still poetic.

Just static public, static private looked reverse-poetic. Smile | :)

Starting to think people post kid pics in their profiles because that was the last time they were cute - Jeremy.

First one... always.

V.

(MQOTD Rules and previous Solutions )

I have this code:

C#

public void mtdProgressbar() {

            prgsBar.IsIndeterminate = false;

            prgsBar.Orientation = Orientation.Horizontal;

            prgsBar.Minimum = 0;

            prgsBar.Maximum = short.MaxValue;

            prgsBar.Value = 0;

            double value = 0;

            prgsBar.Visibility = Visibility;

            UpdateProgressBarDelegate updatePbDelegate = new UpdateProgressBarDelegate(prgsBar.SetValue);

            do
            {
                value += 1;

                Dispatcher.Invoke(updatePbDelegate,   System.Windows.Threading.DispatcherPriority.Background,new object[] { ProgressBar.ValueProperty, value });
            }
            while (prgsBar.Value != prgsBar.Maximum);

            prgsBar.Visibility = Visibility.Hidden;
        }

But i can not create the Thread do fill progressbar, do not work.
The code:

C#

.
.
. 
else{
System.Threading.Thread trd = new System.Threading.Thread(new System.Threading.ThreadStart(this.mtdProgressbar));
                trd.IsBackground = true;
                trd.Start();
mtdTest(); //this method contains only loop for,represents an operation that requires the progressbar
}

I'm using C# and Wpf

Threads can be tricky, what you are running into is a problem with access.. threads by default can not access the ui to update a progress bar because that may create a deadlock.

For the background worker there is a function built in for report progress, but it is limited to only allow for simple updates.

You can however, get around this requirement by doing
.Invoke((Action)delegate() which allows safe access to the ui through a delegate.

I have used this method to update multiple labels, etc.

That should do the trick.

=)

Forbiddenx wrote:
You can however, get around this requirement by doing

.Invoke((Action)delegate() which allows safe access to the ui through a delegate.

Hi, isn't the OP already doing this in his code:

C#

do
{
    value += 1;

    Dispatcher.Invoke(updatePbDelegate,   System.Windows.Threading.DispatcherPriority.Background,new object[] { ProgressBar.ValueProperty, value });
}

?

Of course, the OP didn't disclose the code for 'updatePbDelegate, or show where it's created. In this case I think the problem is elsewhere (see Dave K.'s response).

Google CEO, Erich Schmidt: "I keep asking for a product called Serendipity. This product would have access to everything ever written or recorded, know everything the user ever worked on and saved to his or her personal hard drive, and know a whole lot about the user's tastes, friends and predilections." 2004, USA Today interview

Yes, I do see invoke but it does not look like its used correctly.

It looks to me like his code is trying to access the progress bar ui directly and outside of the invoke.
It looks like he is setting a lot of values, my guess is some of those values are on the ui and that is what is crashing everything.

I think he is going to have to re-write how this works..

=)

You don't put the progress bar in the background thread. It MUST stay on the UI (startup) thread. Your work goes in the background thread and then Invokes a method that updates the progress bar on the UI thread.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak

See here[^]
It's from one of the CP members... (btw)

hope this helps

V.

(MQOTD Rules and previous Solutions )

I'm in my third year of a software development course and will soon be tasked with completing a project to demonstrate my knowledge so far in programming.

I have decided to pick c# as the language as I'm more confident with it and my ideas so far are either a website with a database and/or a shopping cart or else an application like a movie library that has a database and capabilities to update info from the web.

The spec for the project is vague in terms of features and functions as I'm just going by what I've learned in the last three years.

I would be grateful if anyone could give me some feedback on my ideas or any new ideas they may have.

Thanks for your time Smile | :)

Depending on how long you have....
C# and unity go nice together..

=)