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Hello,
I have a destructor in my form, but when I set a break point inside of it, it never breaks.
Am I not supposed to write a distructor for forms?
Is this behavior by design?
How than, should I release resources held by the form?
Thanks in advance,
Shy.
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There aren't any destructors in .NET, as there are no reference counters. The destructor syntax is instead used for a finalizer. The finalizer is called by a background process after the garbage collector has recognised that the object can be freed, but as the form object is one of the last objects to go when you close the application, there will rarely be any garbage collection that can place it in the queue of objects to be finalized.
You should use the events of the form that occurs when it's unloaded, to free it's resources.
---
single minded; short sighted; long gone;
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I see...
And what about non-form classes?
Should I use distructors?
Or maybe leave the destructors out, and keep my Dispose() implementations?
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As Guffa mentioned, C# doesn't have desctructors, but it does have finalizers. Unfortunaately, you use the C++ destructor syntax to declare the finalizer.
Writing a finalizer is usually not required and there are very specific rules that should be followed. Implementing IDisposable is usually only necessary when your class maintains unmanaged resources.
Look at this article[^] for a more in-depth discussion.
-----------------------------
In just two days, tomorrow will be yesterday.
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Thanks a lot guyz...
Happy programming to you all! 
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shyagam wrote: Should I use distructors?
You might want to re-read what Guffa said. He explicitly said there were no destructors in .NET. There are Finalizers which are similar, but not quite the same thing.
If your class holds onto any large amounts of memory, or unmanaged resources or any class that does then you should implement the IDisposable interface. In the Dispose method you release the memory, or the unmanaged resource or dispose the class. In the finaliser method you call Dispose - but that is a last resort. You should not really allow the finaliser to be called at all as it is inefficient. Normally you should Dispose of any object that implements the IDisposable interface.
shyagam wrote: And what about non-form classes?
Any object of a class that implements IDisposable.
shyagam wrote: Or maybe leave the destructors out, and keep my Dispose() implementations?
Keep the finalisers (not destructors). They call Dispose(). The Dispose method does the clear up. You keep the finaliser as a safety mechanism in case the call to Dispose was forgotten about.
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I see...
I'll read some articles about the subject, to get a deeper understanding.
Thanks again.
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Colin Angus Mackay wrote: If your class holds onto any large amounts of memory, or unmanaged resources or any class that does then you should implement the IDisposable interface.
Actually, using large amounts of memory is not any reason to implement the IDisposable interface (unless it's unmanaged memory, of course).
The garbage collector doesn't sort out the objects that can be freed, it sorts out the objects that needs to be kept, and frees everything else. If you remove the reference to an object, the object and all it's members will be garbage collected all at once. As there are no references to the object, the references that it contains are not considered when sorting out the objects to keep. By removing the reference to an object, you also effectively remove all references that it contains.
---
single minded; short sighted; long gone;
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And why would it be? Even after closing the form you may want to show it again.
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It's the main form, so when its closed, the application is closed. 
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I'm writing a client/server application, and I want the client pc to shutdown when
receiving a specific value from server, so my question: is there any way to shutdown
or restart computer from within C# code?.
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You can use the API call, or WMI to do it:
http://pinvoke.net/default.aspx/advapi32/InitiateSystemShutdown.html?diff=y
WMI is shown in VB at the bottom. Easy enough to convert that to C# though.
--
Real programmers don't comment their code. It was hard to write, it should be hard to understand.
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in my solution , when i devide two number , the result is '2.3333333333333333333333333333', so it got error!!!
Parameter value '2.3333333333333333333333333333' is out of range.
how could i manage it?!!
any help could be useful.
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What are you trying to do with the parameter? Show some code, it will help us see what you are doing.
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I've made a windows service and give it the task to write current time at regular intervals of 5 sec.
It worked good at debug mode but when I starts the service from service management it do nothing.?? Al the code that is written in the service start method is correct. Any suggestion??
Please fast.
Thanks
Syed Shahid Hussain
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Syed Shahid Hussain wrote: I've made a windows service and give it the task to write current time at regular intervals of 5 sec.
It worked good at debug mode but when I starts the service from service management it do nothing.?? Al the code that is written in the service start method is correct. Any suggestion??
Where is the time being written to. Does the user that the service is being run under have permissions to write to that location?
If you are trying to write to the UI, has the service been given permission to interact with the desktop?
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I've given two tasks to the service first it creats a file in c:\ that is ???.db and a temp file that is ???.temp. when service starts it creats two files and save current time in ???.db file and when the service stops it deletes the ???.tmp file.
Now both files are created successfully and the ???.tmp file is deleted successfully also but the time is not written in the ???.db file.
I'm new to services. Now gie me the exact solution.
Thanks
Syed Shahid Hussain
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You put the code into the Service Start method?? Nope. A Windows Service should start a seperate threaded component from its Start method. That component is what does all the work of the service you write.
Dave Kreskowiak
Microsoft MVP - Visual Basic
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I've written the action code in start method already.
Any more suggestion.
Thanks.
Syed Shahid Hussain
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Then you'll have to rewrite it. The start menthod is used for starting the service code up, not doing the actual work of the service.
Dave Kreskowiak
Microsoft MVP - Visual Basic
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Thanks i've found the problem that is ; i've used a System.Windows.Timers.Timer control in the service but i have to use System.Timers.Timer object in my service.
Take Care.
God Bless You.
Syed Shahid Hussain
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Thnx,,
Db goes like...
Source Destination Distance
A B 1 //these r entries
now, A is filled in combo1 n b in 2nd.i did it by reader.
But at unable to generate the distance(although query i correct).
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Your message looks like a responce to this[^]. Please press the "reply" button in the appropriate post to reply to it. DO NOT START A NEW THREAD!
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helloz,
how i can convert from hexadecimal to char, i dont want to convert 1 char by 1 chat i want to convert a string of hexadecimanl values like
string dd = "00640065006600670068";
i know that i can ceonvert a single one as
string gg = "\u0064";
but i want to convert a whole of string dd
there is a problem if i define a variable string as:
string hh = "\u";
and i dont want to define it as:
string jj = "\\u"; or @"\u"
because it will give me "\\" not a single one
Thanks alot
Hamody
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Hey guys, i got the solutution which is:
private string HexAsciiConvert(string hex)
{
StringBuilder sb = new StringBuilder();
for (int i = 0; i <= hex.Length - 4; i += 4)
{
sb.Append(Convert.ToString(Convert.ToChar(Int32.Parse(hex.Substring(i, 4), System.Globalization.NumberStyles.HexNumber))));
}
return sb.ToString();
}
Thanks alot
Hamody
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