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1)
But I am helping the GC telling the object has no reference, instead of GC finding itself. Is I am not gaining the performance?
2)
So I can set a large object to null to achieve performance gain
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devin123 wrote:
But I am helping the GC telling the object has no reference, instead of GC finding itself. Is I am not gaining the performance?
You're telling C# that this reference to the object is no longer required. At some point, sometime before your PC totally falls over from lack of memory, the GC will work out that no references are held, and so do garbage collection. I found out the hard way that managed DirectShow leaks memory ( I was loading video files ), and my app was running at a crawl as my memory was full and my disk drive was swapping non stop. GC had not occured.
And why would you gain performance from getting back some memory, unless you have severe memory issues already ?
devin123 wrote:
So I can set a large object to null to achieve performance gain
No, you can Dispose of it to free the memory, and then set it to null. The setting to null is actually irrelevant to performance or memory usage, it's just good coding. This will help if you're in a situation like my example above. You should do this when you have large memory objects flying around, but it will only help performance if excess memory usage is hurting it.
Christian Graus - Microsoft MVP - C++
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But dispose only releases the resources, it does not reclaims the memory.
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I've done this, and I can assure you, it causes the memory to be released, if right away, or through encouraging the GC to release the object, I don't know. However, setting a reference to null definately doesn't do this, and will not help you in any way.
Christian Graus - Microsoft MVP - C++
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So you meant to say that using dispose, we can manually reclaim the memory and also the resouces
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GC reclaims memory, but calling Dispose seems to give it a serious hint, or otherwise, the Dispose methods for bitmaps and movies free the memory in some other way.
Christian Graus - Microsoft MVP - C++
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So dispose does not directly reclaims the memory. It helps GC in more efficient GarbageCollection
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That would be my guess. What I know for sure is that if you call dispose, you'll find your memory situation does not deteriorate where you use a lot of large objects.
Christian Graus - Microsoft MVP - C++
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Thanks Christian, for your help.
Devin
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The dispose pattern if implemented correctly should supress calling the finalize method of the object. The GC when collectiong objects always calls the finalizer of these objects, but if dispose is implemented and the object has been disposed, u might gain this small advantage in performance allthough its probably insignificant.
The main advantage is as been stated before, the release of unmanaged resources and the fact that ur helping the gc manage memory in a more efficient way.
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Here is how it works:
you have a reference to your ".net" object instance
the memory that object occupies is released by the GC when no references are left.
Dispose is used to release native resources , such as filehandles , db connections or memory allocated by some native resource.
so ".Dispose" does not kill the .net object itself , it just tells it to drop its expensive resources.
if you are working with images , eg in DX there are plenty of unmanaged resources behind the scenes , and your .net object is told to drop those directly ... therefore Christian get a big chunk of memory back.
if your object does not hold any references to any native resources (directly or inderectly) you will not gain anything by implementing idisposable on that class.
eg if your class has a big arraylist or array and you set it to null in your dispose method , you will not gain anything since those are managed resources taht will be released by the GC.
//Roger
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I am trying to convert the following code to C# and am having quite a bit of difficulty.
#ifndef API
#define API
#define API_Item 256
Here is what I tried:
#if (!_API)
#define API
public static readonly int API_Item = 256;
Am I way off?
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I'm trying to implement highlighted/selected text format editor funtions by clicking buttons like "bold", "italic", etc.
The problem is how could I get highlighted text from certain textbox?
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string ht = textBox1.SelectedText;
but about formatting you may use richtextbox.
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yeah, you have to use a richTextBox. and with the rich formatting, you could do something like:
richTextBox1.SelectionColor = colors.blue;
that sort of thing.
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Thank you for your reply.
Unfortunally, my code is for a web application but not windows so that I cannot use richtextbox.
And I work on vs2003, which doesnt provide "selectedtext" function for textbox.
But I found a way could solve the problem by javascript pbbly.
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I have an Excel automation engine that collects data from a specified cell in the Execel worksheet. Well when I get the data back and parse it based on a "," I get the following string from the worksheet "\"devbng:BNGDetail\"". Well I need to get rid of the '\' and the extra '"'. Well I have tried everything i could think of
I wrote the following
_serverName.Replace("\\","");
_serverName.Replace('\"',' ');
But no avail, well any help would be greatly appreciated.
Thanks
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There's a Remove method also, isn't there ?
Christian Graus - Microsoft MVP - C++
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Ignore this entire post if _serverName is not a string object.
Strings are immutable, so the code you have now is essentially a no-op, i.e. it's returning a new instance of a string that is not being stored by anything, and the original value of _serverName is unchanged. Have you tried:
_serverName = _servername.Replace("\\", "");
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Hi,
After I am done with the object, when I set that object to null, what I am doing there. (Is it, I am setting manually no references to the object or I am reclaming the memory used by the object or I am doing both)
Thanks
Devin.
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devin123 wrote:
After I am done with the object, when I set that object to null, what I am doing there.
You are setting the reference to the object to null, not the object itself. If there are no references to an object the garbage collector can remove the object from memory. If the reference is a local variable then when the method goes out of scope the reference will no longer exist and the object (assuming no other references) will get cleaned up.
Does this help?
My: Blog | Photos
WDevs.com - Open Source Code Hosting, Blogs, FTP, Mail and More
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Hi,
I know GC does memory management manually. If i want to manually reclaim the memory of an object, how can I do it.
Thanks
Devin
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