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In a simple dialog
namespace projectname
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void FormDataChanged(object sender, EventArgs e)
{
blah.........
}
private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
FormDataChanged(???????????, ?????????);
}
}
}
If I want to use the FormDataChanged function when I process the change in a listbox or a checkbox or whatever, what should I supply as the arguments. I suppose I have just dived in to C# and it's a bit different to what I am used to. I am not using either "sender" or "e" in the FormDataChanged function, I just want to know what is/should be in there, is it the item on the form itself that is the object, e.g. in the example above, is it the listbox itself, should it be "this" as the 1st parameter, and where does its EventArgs come from?
thanks for any help
If I put FormDataChanged(sender, e) that seems like it should be correct, but maybe I just need to find out a bit more about how the sender/args constructs work in more detail
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In an event handler method, sender is the object that is generating the event, and e are event-specific arguments (for example a MouseClick event sends the mouse button that was clicked). If e is of type EventArgs, that means there are no specific argument for an event.
If you don't need these informations, you can easily ignore the parameters.
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ldsdbomber wrote: private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
FormDataChanged(???????????, ?????????);
}
Hi,
you should avoid calling event handlers directly; there are some alternatives:
1.
some events can be fired by calling a specific method, such as button.PerformClick()
2.
you can create a method that contains the bulk of the event handling and call that directly, without needing any special parameters. Example (see Timer_Tick method):
private void checkbox1_CheckChanged(object sender, EventArgs e) {
somethingHasChanged(sender as Checkbox);
}
private void listbox1_SelectionChanged(object sender, EventArgs e) {
somethingHasChanged(sender as Listbox);
}
private void Timer_Tick(object sender, EventArgs e) {
somethingHasChanged(null);
}
private void somethingHasChanged(Control c) {
if (c!=null) Console.WriteLine("Something got changed relating to Control "+c.ToString());
...
}
Luc Pattyn
I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages
Local announcement (Antwerp region): Lange Wapper? Neen!
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Many thanks.
Do you have any opinions as to a good reference book that would include this kind of information, i.e do I want a book on C# itself, or is it Windows Forms, or Visual Studio specific?
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Sorry, no, I don't generally recommend specific books. Some people prefer a specific author, others a publisher.
The books I own I have bought at various points in time, choosing from whatever collection was available at the nearest book store at that time.
I often like the Microsoft books, including the Step-by-Step series (which is tutorial, not reference).
Luc Pattyn
I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages
Local announcement (Antwerp region): Lange Wapper? Neen!
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Sorry, what I meant was not a specific book, but a specific class of book. i.e. does a general purpose C# book contain details about controls and event handlers, or is that specific to windows forms etc. And for handling and tokenising strings and dialog data, are there specific types of books for that or... I realise this question is a bit wishy washy!
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What is in a book is what an author chooses to be there (the publisher permitting).
Some books are purely language-oriented; others are technology oriented (e.g. database) but require a language for their examples, and may or may not offer an introduction to the language too.
Windows Controls have existed for a long time, but they evolve, and their capabilities may be reduced or augmented by some framework (MFC, .NET, ...).
My best advice is to go to the book store and make your own choice. That's what I do and recommend.
Luc Pattyn
I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages
Local announcement (Antwerp region): Lange Wapper? Neen!
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Hello everybody, I have started again working my own windowsmediaplayer. I had included wmplibs in my code, but I could only see the interface(control), I couldn't activate it. Internally it can play for an audio, but not with the wmp control. My question is, how to activate the control and or how to play media using the control?
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Hi,
You might be able to get some ideas if you could go through Chapter 16 of this book 
Best wishes!
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Hi leapsword, I need free source. I am very far away from where you are or the book. Thank you
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Yonathan1111 wrote: Hi leapsword, I need free source.
Hi,
Free source are certainly not possible to be given, cuz:
1. They require other people's hard work on;
2. We are here only for the reason to try to help each other with problems, but not for the sake of giving a solution;
So, very sorry to say, but you probably need to go and buy a book to read, or do some research by searching on internet. 
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Hi everybody, I think you understood me in wrong way, I just want to say, I couldn't afford the book it is not for the free code. Thank you.
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Huh, Sorry, I must have read your previous post wrong. If you need free source of that book, you can just google the name of that book with keyword "rapidshare", then you should have few links to be accessed. Good luck!
Sun
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Hi All,
As my subject may suggest, I am having a strange problem. The latest test release of my application (WinForms) will completely freeze once the screensaver is enabled, I can also replicate this by locking the computer and unlocking, also if a change display settings it happens (this I read in a post where someone else had the issue, but could not find any solutions on the few hits I managed to find.
When I say freeze, I mean completely not responsive, even to the point of it not displaying the usual 'Not Responding' text.
This was not the case in the previous test version, but I have pretty much removed everything since that last version and still an issue.
I know it's not much help, but there is so much different code that I cannot post any examples.
Has anybody seen or heard of this before that could maybe shed some light?
Thanks
Life goes very fast. Tomorrow, today is already yesterday.
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That's a common problem if you're working with DirectX (the hardware surface gets lost when you lock or go to screensaver, and needs recreating, which will break your app if it doesn't handle that)
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No DirectX I'm afraid
Life goes very fast. Tomorrow, today is already yesterday.
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I recently had a similar problem with a Silverlight control shown in a WinApp through a WebBrowser control.
Would be nice to have some idea on how circumvent this.
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Thanks but No Silverlight, No WebBrowser control. Have only been using the same standard .Net controls I have used throughout the application. I have not added any control that I have not previously used so that shouldn't be a problem.
Life goes very fast. Tomorrow, today is already yesterday.
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Yes, I understand, I was only taking advantage of your request hoping to have some answer to my issue too.
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Fixed my issue, see my answer. Not sure it will help you with yours thou but maybe an idea of what to look for
Life goes very fast. Tomorrow, today is already yesterday.
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I found the problem. Basically the issue is with a static function I am using that converts RichText to plain text. This function was failing when being called from a background worker (which must be starting when the windows display changes, but that'a a different bug)
The function uses a RichTextBox to do the conversion, I have now added a line of code to Dispose() the RTB before returning the function and problem solved. I don't know the technical details behind why it cause a problem but hopefully this may help anyone with a similar issue.
Life goes very fast. Tomorrow, today is already yesterday.
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Hi all,
Some background info: I am trying to represent free/busy information for boardrooms.
I am looking for a control similar to the one found within Outlook appointment scheduling, with one extra addition, it must be displayed as a chart  (scheduling chart). I have looking through the CP articles, but can only locate ASP like controls. Does anyone perhaps have a bookmark or something useful that can point me in the right direction?
Many thanks in advance
Kind regards,
The only programmers that are better C# programmers, are those who look like this -> ![Green Alien | [Alien]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/alien.gif) |
![Java | [Coffee]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/coffee.gif) Programm3r
My Blog: ^_^
modified on Tuesday, October 13, 2009 6:10 AM
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I believe this may be a threading issue that i need better understanding with, please.
I have a WorkerClass, that takes in various parameters and then calculates complex math over multiple CPU cores (threaded). It builds an array of data used elsewhere in app. this part works great.
The problem is that i may need up to 100 instances of this class, and im not sure how to control the execution of this part. Heres sorta the flow im trying to get at:
Void BeginCalculation()
{
Calc1 = new WorkerClass(param1, param2, param3);
Calc1.Start();
Calc2 = new WorkerClass(param1, param2, param3);
Calc2.Start();
Calc3 = new WorkerClass(param1, param2, param3);
Calc3.Add(Calc1.Array, Calc2.Array);
}
I really need to control when Calculations begin, because a few steps will combine data from previous steps. I also have the WorkerClass updating a public Status object, so i need to keep that feature in.
The only way i know how to control the flow here, is if i have a thread that is infinitely looping, and checking the thread state of the current calc instance thread. Then (on ThreadsAlive = False) calling a MoveToNextCalc() to start next. But somehow this seems like the wrong approach. Is it? Does someone have a better approach to this?
This is also using XNA, so i need to avoid tying up the Draw/Update steps, with lots of work. And really dont want tons of threads running at same time. Its currently 1 WorkerClass instance spawning 1 thread per CPU. Each thread working on a seperate section of an array.
I hope thats enough info to work with. Any help on best approach to this, greatly appreciated!
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Use wait handles. Work with AutoResetEvent and WaitOne() method on that. You need to supply AutoResetEvent instance to the worker class and once operation is done, call Set() on wait handle. Here is a modified code.
Void BeginCalculation()
{
AutoResetEvent waitHandle = new AutoResetEvent(false);
Calc1 = new WorkerClass(param1, param2, param3);
Calc1.Start(waitHandle);
waitHandle.WaitOne();
Calc2 = new WorkerClass(param1, param2, param3);
Calc2.Start(waitHandle);
waitHandle.WaitOne();
}
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Nava!
Thank you much for the quick solution. It was perfect for my needs. And helped me move closer to understanding threads! 
cheers! -ms
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