Re: C# VS10 and error "no suitable method to override" issue - books for beginners - C# Discussion Boards

C# VS10 and error "no suitable method to override" issue

15-Dec-11 14:20

... since this is a kind of a long response, with a lot of content that does not relate directly to the first thread/set of comments on the OP's thread, and code examples, I will post this here as a separate "fresh" response to the OP ...

Miwin Solutions wrote:
but I may have up to 250 buttons

Hi Mike,

Like the other commentators on this thread, I "gasp" at the idea of 250 buttons ! But, I also assume it's possible that not all of them are shown/visible at the same time. "bunches of them" on each TabPage in a TabControl is one idea that comes to mind.

Some more information from you can help further refine the proposed solutions here: and, imho, definitely influence implementation strategy:

1. how are these buttons "organized:" are they in a row, column matrix ? Are they "all over the place" ? Are they inside different containers, or in nested containers ?

2. will every one of them invoke/execute/call a unique function (perhaps in addition to some common functionality they all invoke) ? Or, will "bunches" of them execute the same code ?

2a. a rarer case (?) would be the requirement that code that each (or some number of) Button(s) executes changes during the application lifetime.

3. is the unique code each, or "bunches of," Buttons will call "elaborate," or "simple" ?

If you use a Tag, you have to cast the Tag back to whatever object type you require ... again I think this is no big deal, unless you are getting a thousand button presses a minute ... and then ? ... you're going to need some kind of "selector structure" which that converted Tag can be used to access to select the code required to be invoked. That could be a switch statement, a nested if then/else block (please no, anything but that one), or, as Luc suggested, a Dictionary look-up.

Hints:

1. case statements in a switch block can be "or'd;" to create "bunches," all with the same handler:

case "button4":
case "button5":
  Console.WriteLine((sender as Button).Name);
  break;

But, once written that way, you are not going to be able to modify without re-coding, and re-compiling.

2. executable code (anonymous functions) can be stored directly in a Tag object and invoked with one extra level of casting: you'll need a delegate:

private delegate void uniqueButtonCodeToExecute();

And, you can set code to be executed in the Click EventHandler like this:

SomeButton.Tag = new uniqueButtonCodeToExecute(() => Console.WriteLine("in Button8's unique code"));

And then, the Click EventHandler for each Button could work like this:

private void ButtonUniqueCode_Click(object sender, EventArgs e)
{
    ((sender as Button).Tag as uniqueButtonCodeToExecute)();
}

3. Similarly, you could have a Dictionary with KeyValue Pairs whose Keys were of Type object, and whose Values were of Type anonymous function/method, or valid code for calling an external named function/method:

// using the same delegate shown above:
private Dictionary<object, uniqueButtonCodeToExecute> ButtonCodeDictionary = new Dictionary<object,uniqueButtonCodeToExecute>();

You'd create the Dictionary entry per Button like this:

ButtonCodeDictionary.Add(SomeButton, () => Console.WriteLine("in Button8's unique code"));

Then, the Button Click EventHandler could be:

private void ButtonsForWhatEver2_Click(object sender, EventArgs e)
{
    ButtonCodeDictionary[sender]();
}

What if you want get the definition of the code unique to each Button out of the assignment as anonymous function (which I'd recommend for code clarity, maintenance, re-usability, etc.) ? Then you can use something like this:

ButtonCodeDictionary.Add(theButton, () => SomeUniqueButtonsMethod("Button8"));

In this example the lambda notation () => does the right thing to set the delegate to an externally defined method, passing a parameter: here's what the function could look like:

private void SomeUniqueButtonsMethod(string buttonName)
{
   Console.WriteLine(buttonName);
}

So, you have a wide range of options to use here.

My own choice, assuming 250 buttons, and every one of them executing a different method/function, would be to use the Button's Tag, store one of a sequence of integers in each Tag, and then use the Tag cast to an Int as the selector in a big switch statement: after all, you could execute code anywhere in the application, inside any of those switch cases that are selected, via techniques such as cross-class method/function exposure, invoking static members of a static "uber-class" that all classes could see, etc.

But, I remain convinced that a scenario that uses 250 buttons, each with unique code to be executed, is probably a sign that the code strategy, the architecture, really needs to be changed.

I've been playing around with storing executable code in Dictionaries for several years: for example, in this article for DevX:[^], written for .NET 2.0, in which I make the Value of the Dictionary's KeyValue Pairs, an actual delegate definition itself, and then use "DynamicInvoke" to execute them (scroll down in the article to the section titled: "Introducing Dynamic Code Dictionaries").

When I consider the brief span of my life, swallowed up in the eternity before and after, the little space which I fill, and even can see, engulfed in the infinite immensity of spaces of which I am ignorant, and which knows me not, I am frightened, and am astonished at being here rather than there; for there is no reason why here rather than there, now rather than then.

Blaise Pascal

modified 15-Dec-11 20:58pm.

Deborah Palmer McCain14-Dec-11 6:27

Re: C# VS10 and error "no suitable method to override" issue

14-Dec-11 6:27

Thank you to those who made an attempt to assist me.

The problem is resolved. All I had to do was double click on Line 14 in the Error List in VS 10, and the fix code was inserted.

The application now runs correctly.

Any new developers might consider picking up Dan Clark's Beginning C# Object Oriented Programming. I could have saved myself about 5 hours of frustration, had I skipped to Chapter 5 and read it.

Richard MacCutchan14-Dec-11 22:23

Richard MacCutchan

14-Dec-11 22:23

I would also suggest Charles Petzold's .NET Book Zero[^] as a great (and free) introduction to the basics of .NET and C#.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

Re: C# VS10 and error "no suitable method to override" issue

Deborah Palmer McCain15-Dec-11 5:27

Re: C# VS10 and error "no suitable method to override" issue

15-Dec-11 5:27

Thank you for the suggestion. I am on my way to retrieve the Petzold reading.

BillWoodruff15-Dec-11 14:30

Re: C# VS10 and error "no suitable method to override" issue - books for beginners

15-Dec-11 14:30

re Dan Clark's book: in terms of new developers, who are not coming from a more formal development methodology, experienced in structured-code informed by CS theory background, not already having experience with flow-diagrams, UML, etc.

I specifically would not recommend this book: the first sixty pages are general theory, and you don't get to the C# "meat," until much later in the book. But, if you are person for whom state-machine concepts, flow-chart diagrams, and UML models, are already salient: go for it Smile | :)

There are many better introductory books, imho, for C#, among them I vote for ones by Jesse Liberty, Matthew MacDonald, Troelsen, Sells, etc., perhaps the one from Deitel, and even Petzold's very old first book, as well as his current free one mentioned.

best, Bill

When I consider the brief span of my life, swallowed up in the eternity before and after, the little space which I fill, and even can see, engulfed in the infinite immensity of spaces of which I am ignorant, and which knows me not, I am frightened, and am astonished at being here rather than there; for there is no reason why here rather than there, now rather than then.

Blaise Pascal

Deborah Palmer McCain15-Dec-11 16:35

Re: C# VS10 and error "no suitable method to override" issue - books for beginners

15-Dec-11 16:35

Bill:

I noted the authors you list, and will research further. As I do not have a background in CS (other than the watered down clases provided for teaching credentialing) I scoured the reviews on iProgrammer and Amazon.

There are going to be issues with most books and/or tutorials, and I find myself irritated with the "casual" editing(simple errors in grammar/syntax) in many books, but I "deal". It's almost as if there is a race to the publisher, and then a laundry list posted of errata (?). I am not speaking of language (the u in color outside of the US), but rather when the word should be window, and widow is the printed text. Again, I rant.

As to the Clark book, I enjoy his "teaching method" as he explains how something works and why, and I don't feel stupid, just ignorant. I admit to enjoying DFD so I was probably enchanted.

Thank you again for your insight and recommendations.

Deborah

BillWoodruff15-Dec-11 18:40

Re: C# VS10 and error "no suitable method to override" issue - books for beginners

15-Dec-11 18:40

Hi Deborah,

fyi: I've been involved with technical editing and documentation strategy for many years: most recently as a paid technical reviewer for two major .NET books from Addison-Wesley.

I omitted from my recommendations what I consider to the ultimate C# book, the palladium, the ne plus ultra, mainly because I believe it is a very advanced book: Jon Skeet's "C# in Depth"[^] (Manning Press, 2nd. edition now available).

My own review of that book is here:[^]. But you'll note some of the most voted-up reviews on Amazon for this book recommend it as a beginner's book.

I think the type of book that is "best" for someone starting any computer language, embedded in (an expression of) a complex FrameWork, and "incarnate" in a complex IDE, really is not a one-size-fits-all "answer."

What I do know is that in my own experience, as I immediately jumped on the C# bandwagon several years ago, from VB6, was that Petzold's first book helped me get "off the ground," and then Jesse Liberty's book, Programming C# (O'Reilley ... new revisions issued several times), really gave me what I needed, in conjunction with Matthew MacDonald's very clean expository prose.

For myself, it is only at this point, that I am able to read Troelsen and really follow the content about what happens "under-the-hood" in the FrameWork and the CLR, and find that salient, and relevant. And, only at this point, that I can find, in constantly re-reading the chapters in Skeet's book, continuing re-appraisal of my own understanding (and I'm still a long way from mastery of the depths of Skeet's astounding mind's thoughts and concepts).

But, that's just the story of one pilgrim: someone with a good academic CS background, someone who's already "grounded in OO," could have, I believe, very different needs, and make very different choices for a first book.

And, perhaps, also a matter of temperament ? Some folks cognitive style in technical problem-solving is very much top-down: they are most comfortable starting very high-level abstractions, and moving "down" to code-on-the-ground.

People like me are more "bottom-up" in learning style: I have to be constantly experimenting in code, trying out ideas, observing what happens, and then going back to the conceptual level, and the books for inspiration and, hopefully, understanding, followed by step-wise refinement of my own techniques.

best, Bill

When I consider the brief span of my life, swallowed up in the eternity before and after, the little space which I fill, and even can see, engulfed in the infinite immensity of spaces of which I am ignorant, and which knows me not, I am frightened, and am astonished at being here rather than there; for there is no reason why here rather than there, now rather than then.

Blaise Pascal

Deborah Palmer McCain15-Dec-11 20:37

ShowDialog not displaying form.

15-Dec-11 20:37

Bill:

Thank you for your very detailed explanation of choices. As you indicate, cognitive style plays a great part in the resources with which people will be comfortable. It's never a one size fits all. This is one of the difficulties in college classes, where there is an assigned text, which is why I elected not to enroll in a programming class as I prepare to return for my second Master's degree.

When I first began learning C#,which appealed to me of all of the languages (probably because it's case sensitive...but who knows) I recognized I am top down in my own thoughts, but because I taught both middle school and adults, lessons had to be presented in a bottom up fashion. When I first began teaching, I was very much top down, and my students crashed and burned. With C#, I have just recently begun to "mess" with code (some of the problems posted here), but am not proficient enough to offer input. I like to see how I can solve the errors I immediately recognize before clicking F5.

I have printed your post as a reference for authors. I did go to Amazon and research the authors you had initially recommended, and added them to my wish list. I really need to "discover" if I am a developer. Research is my absolute love, and I was initially hired by my client to be a technical researcher, and then he offered the opportunity of learning to code. I hope I can live in both worlds.

You may be interested in the book, Designing with the Mind in Mind by Jeff Johnson. He discusses UI (another passion along with UX), and the book is truly marvelous.

Best,
Deborah
"UberElmR"

mnaveed14-Dec-11 6:23

mnaveed

14-Dec-11 6:23

Hi i am using a web browser control on a win form to display a webpage. it was working fine on xp 32bit.
During testing on Windows 7 64bit after some time i m unable to see my form.
Showdialog() call from button only display the icon and title of my form in taskbar, Form is not visible on the screen. only solution to make it work again is to remove my windows profile and create it again.

i cant understand the problem please help.

i am using VS2010 and C#

thanks

Nav.

Re: ShowDialog not displaying form.

BillWoodruff14-Dec-11 22:03

Error 1067 C# windows service

14-Dec-11 22:03

You need to explain what your structure here is in more detail.

1. is the WebBrowser in a Container Control (like a Panel) ?

2. what exactly makes you unable to see your form ? what's covering it up, or on top of it ?

3. where is the Button that triggers the use of ShowDialog ?

4. what is the purpose of the Dialog show ?

5. how is the TaskBar involved here ?

6. what is the "Windows profile" you say you have to remove ?

When I consider the brief span of my life, swallowed up in the eternity before and after, the little space which I fill, and even can see, engulfed in the infinite immensity of spaces of which I am ignorant, and which knows me not, I am frightened, and am astonished at being here rather than there; for there is no reason why here rather than there, now rather than then.

Blaise Pascal

eyesark14-Dec-11 4:07

eyesark

14-Dec-11 4:07

I was doing a C# windows service. the service installs and runs well on my machine, but when i deploy on server (Windows server 2003), and try to start it, i get the dreaded 'Error 1067: application terminated unexpectedly'!
What to do?
some of the code is shown below:

i was doing a C# windows service. the service installs and runs well on my machine, but when i deploy on server (Windows server 2003), and try to start it, i get the dreaded 'Error 1067: application terminated unexpectedly'!
What to do?
some of the code is shown below:

[RunInstaller(true)]
public partial class MessagingInstaller : Installer
{
    public MessagingInstaller()
    {
        InitializeComponent();
    }
}

public partial class MessagingService : ServiceBase
{
    //declare the message sending logic
    private MessagingLogic msglgc;
    //private readonly EventLog _log = new EventLog { Source = "MessageLogger" };

    public MessagingService()
    {
        InitializeComponent();
    }

    //create new instance of the message sending logic and/or start service
    protected override void OnStart(string[] args)
    {
        if (!EventLog.SourceExists("MessageLogger"))
            EventLog.CreateEventSource("MessageLogger", "Event Logger");

        var _log = new EventLog { Source = "MessageLogger" };

        try
        {
            if (msglgc == null)
                msglgc = new MessagingLogic();

            msglgc.Start();
        }
        catch (ArgumentException exception)
        { _log.WriteEntry("OnStart Error: " + exception.Message); }
    }

    //stop the service
    protected override void OnStop()
    {
        if (!EventLog.SourceExists("MessageLogger"))
            EventLog.CreateEventSource("MessageLogger", "Event Logger");

        var _log = new EventLog { Source = "MessageLogger" };

        try
        {
            if (msglgc != null)
                msglgc.Stop();
        }
        catch (ThreadAbortException exception)
        { _log.WriteEntry("OnStop Error: " + exception.Message); }
    }
}

Please help! I need the solution as soon as possible

modified 14-Dec-11 11:00am.

PIEBALDconsult14-Dec-11 4:34

PIEBALDconsult

14-Dec-11 4:34

Does msglgc get initialized to null? Does it keep running? And shouldn't the Stop method set it back to null?

Richard MacCutchan14-Dec-11 5:58

Richard MacCutchan

14-Dec-11 5:58

Does the new log get created, do you see any messages, normal or exception ...? Try and gather some more information about exactly where it is failing.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

jschell14-Dec-11 9:18

jschell

14-Dec-11 9:18

eyesark wrote:
Please help!

You are assuming that only one possible exception can occur in OnStart.

However if any exception occurs in there then windows will think that the service didn't start.

You can look at System.ServiceProcess.ServiceBase.AutoLog.
If set to true, before any real processing then if OnStart exits with an exception then an event log entry will be written with the exception stack trace.

Pete O'Hanlon14-Dec-11 11:22

Pete O'Hanlon

14-Dec-11 11:22

I suspect that the problem is to do with registering the event source. If you don't have enough privileges to do this, the application will abort at the point you are trying to do this because you are creating it outside of the try/catch block.

Forgive your enemies - it messes with their heads

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

Run the application once

sarang_k14-Dec-11 3:07

sarang_k

14-Dec-11 3:07

Hi all,

I have created one windows setup application,when i installed it on the system if i click two times the application is running two times as it should run once.

How can i solve it ?

Thanks in advance.

Wayne Gaylard14-Dec-11 3:26

Wayne Gaylard

14-Dec-11 3:26

You should run your app using the Mutex class, something like this:-

bool isNew = true;
using (Mutex mutex = new Mutex(true, "yourAppName", out isNew))
{
    if (isNew)
    {
        Application.Run(new MainForm());
    }
}

If the app is aplready running and you would like it to be given focus you need to use a Win32 API method called SetForegroundWindow which I'm sure you could find an instance of on Google.

Hope this helps

When I was a coder, we worked on algorithms. Today, we memorize APIs for countless libraries — those libraries have the algorithms - Eric Allman

BobJanova14-Dec-11 3:43

BobJanova

14-Dec-11 3:43

I didn't know about this. Very handy.

Wayne Gaylard14-Dec-11 3:52

Wayne Gaylard

14-Dec-11 3:52

Thanks!

When I was a coder, we worked on algorithms. Today, we memorize APIs for countless libraries — those libraries have the algorithms - Eric Allman

thatraja14-Dec-11 4:23

thatraja

14-Dec-11 4:23

Here 5+ alternatives
Run Only One Copy Of Application[^]

thatraja

My Dad had a Heart Attack on this day so don't...
Pompeyboy3 here | Nobody remains a virgin, Life screws everyone Sigh | :sigh:

Luc Pattyn14-Dec-11 9:26

Luc Pattyn

14-Dec-11 9:26

WARNING: all the schemes that have been mentioned to you do not prevent the app from launching a second or third time; all they do is try and make the app terminate pretty soon if it isn't the first instance.

Smile | :)

Luc Pattyn [My Articles] Nil Volentibus Arduum

BillWoodruff14-Dec-11 22:13

14-Dec-11 22:13

Luc Pattyn wrote:
all the schemes that have been mentioned to you do not prevent the app from launching a second or third time

Even the one from Wayne G. using a Mutex ?

thanks, Bill

When I consider the brief span of my life, swallowed up in the eternity before and after, the little space which I fill, and even can see, engulfed in the infinite immensity of spaces of which I am ignorant, and which knows me not, I am frightened, and am astonished at being here rather than there; for there is no reason why here rather than there, now rather than then.

Blaise Pascal

Pete O'Hanlon14-Dec-11 22:15

Pete O'Hanlon

14-Dec-11 22:15

It still has to start to detect that there's another instance running. It's not that they don't stop the appearance of an app not being started again, but there will always be a finite period of time where the second instance has spun up - even if it then terminates.

Forgive your enemies - it messes with their heads

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

BillWoodruff14-Dec-11 22:13