Parent SPWeb object as we dont have information on it if it is actually a reference of current context SPWeb internally. Documentation states that we should never dispose off the current context SPWeb object as sharepoint functionality internally depends on it.
Problem is that there also isn't any documentation on whether you should dispose ParentWeb object when you call SPListItem. BreakRoleInheritance but according to this you need to:.
The objects are created specifically in the SPFeature. GetSiteAndWeb method based on Reflector. The FeatureActivated method is an inherited abstracted method and is not invoked through a handler model. The methods are called directly in the SPFeature.
DoActivationCallout method. I would agree that I think it is probably proper to not dispose of them but I sometimes read contrary information out on the net so I'm looking to see if anyone can provide information to the contrary. To add a little on this. Properties and methods like SPSite. OpenWeb andSPSite. RootWeb require Disposal because new objects are being created within the methods and properties. This can be seen in Reflector;. Farm: return this.
WebApplication: return this. Web: return this. This would be persisted as lower case — which was wrong. Well, this should be pretty clear:. After all, the URL to a particular page contains:. Suffice to say, with all those optional bits, decomposing a URL to find the site is really hard. There is, however, a slightly obscure way of find this.
Check out the examples in there. But it is useful to know. Well, Roger Lamb has an excellent page showing patterns that can leak memory, and how to avoid them.
This should be mandatory reading for SharePoint devs. Previously mentioned here — but this is a better link. I like property bags in things. But my question is Dispose needs to implement any logic?
Does it have to do something? Or internally when Dispose is called signals GC that is good to go? I checked the source code for the TextWriter for example and Dispose has no implementation.
Show 4 more comments. In practice, you don't have to worry about destruction, it just works and it's great : Dispose must be called on all objects that implement IDisposable when you are finished working with them.
Actual variable scope In both languages the variable can only be used in the same scope as it was defined - class, function or a statement block enclosed by braces.
C Object references Jon Skeet compared object references in Java to pieces of string that are attached to the balloon, which is the object. Igor Zevaka Igor Zevaka Igor: By going 'out of scope' I mean that the object reference is out of context and cannot be referred to in the current scope. Surely this still happens in C. Craig Johnston, don't confuse variable scoping used by the compiler with variable lifetime which is determined by the runtime -- they are different.
A local variable may not be "live" even though it is still in scope. Craig Johnston: See blogs. The runtime is free to analyze the code that it has and determine what there are no further usages of a variable beyond a certain point, and therefore not keep that variable live beyond that point ie not treat it as a root for the purposes of GC. Tuzo: True. That's what GC. KeepAlive is for.
Craig Johnston: No and Yes. No because the. NET runtime manages that for you and does a good job. Yes because the job of the programmer is not to write code that just compiles but to write code that runs. Sometimes it helps to know what the runtime is doing under the covers e. One could argue that it's the type of knowledge that helps to separate good programmers from great programmers. Show 3 more comments. WriteLine "object created" ; DoSomething a ; Console.
Glorfindel Brian Gideon Brian Gideon What if a is a private member field in a class? If a is not set to null the GC has no way of knowing if a will be used again in some method, right? Thus a will not be collected until the entire containing class is collected.
Kevin: Correct. If a were a class member and the class containing a was still rooted and in-use then it too would hang around. That is one scenario where setting it to null could be beneficial. Your point ties in with a reason why Dispose is important--it's not possible to invoke Dispose or any other non-inlineable method on an object without a rooted reference to it; calling Dispose after one is done using an object will ensure that a rooted reference will continue to exist throughout the duration of the last action performed on it.
Abandoning all references to an object without calling Dispose may ironically have the effect of causing the object's resources to occasionally get released too early. This example and explanation doesn't seem definitive on the hard suggestion to never set references to null. I mean, except for Kevin's comment, a reference set to null after it is disposed seems pretty benign , so what is the harm? Am I missing something? Add a comment. Yes, you should dispose of objects that implement IDisposable.
If you have a long-lived or even static reference to a large object, you want to null it out as soon as you're done with it so that it's free to be reclaimed. If you're ever "done with it" it shouldn't be static. If it's not static, but "long-lived" then it should still go out of scope soon after you're done with it. The need to set references to null indicates a problem with the structure of the code. You can have a static item that you get done with. Consider: A static resource that's read from disk in a user-friendly format and then parsed into a format suitable for program use.
You can end up with a private copy of the raw data that serves no further purpose. Real world example: The parsing is a two-pass routine and thus can't simply process the data as it's read.
Then it should not store any raw data in a static field if it's only used temporarily. Sure, you can do that, it's just not good practice for exactly this reason: you then have to manage its lifetime manually. You avoid it by storing the raw data in a local variable in the method that processes it. The method returns the processed data, which you keep, but the local for the raw data goes out of scope when the method exits and is automatically GCed.
Show 2 more comments. Chris Schmich Chris Schmich But won't the garabage collector call Dispose? If so, why would you need to call it? Unless you call it explicitly, there is no guarantee that Dispose will be called. Also, if your object is holding on to a scarce resource or is locking some resource e. Waiting for the GC to do that is suboptimal.
GC will never call Dispose. GC might call a finalizer which by convention should clean up resources. If you need deterministic finalization you must implement what i think is called a critical handler. The CLR has special handling of these objects to guarantee that they are finalized e. John Saunders k 24 24 gold badges silver badges bronze badges.
Yort Yort 6 6 silver badges 22 22 bronze badges. Andre Andre 1, 9 9 silver badges 20 20 bronze badges. Don't listen to leppie. Memory profile tools can help with things like that, but it can be tricky. GetRecord keys[i] ; record. Dispose is called. GvS GvS 51k 16 16 gold badges 98 98 silver badges bronze badges. From experience I'd also advise you to do the following: Unsubscribe from events if you no longer need them. Set any field holding a delegate or an expression to null if it's no longer needed.
A good place to do this is in Dispose , but sooner is usually better. Marnix van Valen Marnix van Valen What do you mean about 'events and delegates' - what should be 'cleaned up' with these?
Craig - I edited my answer. Hopefully this clarifies it a bit. Hui Hui 41 2 2 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name.
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