[2005] .net Garbage Collection And Primitives?
Jan 29, 2009
Is the memory from primitive data types (int, char,etc) immediately released once they leave scope, or added to garbage collection for later release?
consider:
For x as integer=0 to 1000
dim y as integer
Next
If this doesn't add 1000 integers to the garbage collector for clean up later,how does it treat string objects? would this create 1000 strings to clean up later?
For x as integer=0 to 1000
dim y as string=""
Next
How about structures that contain only int,string,etc... data types?
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Jul 23, 2010
I thought that when a variable went out of scope (like a variable declared within a method - when you exit that method the variable is out of scope) then it was eligible for garbage collection and when it was garage collected the Dispose method is called on it. Now I know that it does not get disposed immediately but I assumed it would be basically as soon as the process starts to take up quite a bit of memory.However, I found that my app's memory usage seems to constantly increase when I dont manually Dispose of a specific method local variable. Of course its good practice to call Dispose and ordinarily I would but I just didn't realise that this particular class actually implemented IDisposable. The class in question was the System.DirectoryServices.SearchResultCollection class, and I was looping through the items in it like so:
[Code]...
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Jan 11, 2011
I'm creating a windows forms program and have recently noticed a large amount of memory slowly being eaten by the application. I went through my program and tried to tie up as many loose ends as I could in relation to object creation but noticed that the program would still keep memory for every form loaded until it eventually crashed.
I decided to make a simple test program which sole purpose is to pop-up a new form with a few controls, wait for 200 milliseconds, then close the form and repeat the process 30 times every time I hit a button. I found it caused the same behavior, even with the only new object creation being that of the form. So, I decided to manually invoke the garbage collector in a subroutine which handles the formclosed event. During tests I would get some memory back occasionally, but not enough to make a difference in the long run. So I start setting the form variable to nothing before I called GC.collect(). The program will initially eat a few 1000K of memory before leveling off and using only 20-40K for every 30 forms created.
Now what I'm wondering is, what is the point of an automated garbage collection system if it requires constant manual evocation and explicit dereferencing of all new objects to be effective? Have I completely lost grasp on the scope of VB.Net forms and it simply never marks forms as available memory to be cleared?I would have thought object memory references created within a form would be marked as usable when the form's close or dispose routine is called and no references to objects created within the form exist anywhere outside the closed form.
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Sep 22, 2009
I am trying to create radiobuttons, and then create code for them after they are created. I have the code to create the radiobuttons. What I want to do is create a sub for the event of changing the check value for the radiobutton. Or to have the check value recognized by a button click. For example, you click the button and if the first radiobutton has the circle filled then a msgbox comes up and says hurray. My code so far is this:
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Nov 2, 2010
I am using a function from a dll in unmanaged code that requires a callback to my managed code in Visual Basic 2010. The callback is asynchronous and is called continuously over the life of the application. What's the best way to protect the callback function from the garbage collector? Right now it is being collected after several dozen calls from the dll.
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Feb 21, 2012
I've been doing some reading on garbage collection in .NET and I was hoping for some clarification. So, as I understand it if I declare a public shared class variable, the GC will never get rid of it. Is this correct?Also, what then of private variables? Take the following example:
public class myClass
private shared myString As String
public sub ChangeString(newString As String)
[code].....
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Oct 5, 2010
I have a callback function in a C+ dll:
<UnmanagedFunctionPointer(CallingConvention.Cdecl)> _
Public Delegate Sub DeviceDetectionEvent(ByVal YasdiEvent As YASDIDetectionSub, ByVal DeviceHandle As UInteger, ByVal param1 As UInteger)
[code].....
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Oct 6, 2009
Datatable object within class function + garbage collection?
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Feb 8, 2011
Here's the scenario, winforms application, monitoring via Task Manager Processes Tab.On initial launch spins up to ~61,000K (initial data grid and data loads)If I minimize the application, not touching or doing anything the Mem usage drops to 1,380K.When I restore the application is spins back up to only 5.8K
So my question is, does the minimize send some internal message to clean up resources since the application in question is not in focus?The first app I noticed this in happens to be VB.NET, but I've observed the same behavior in my main C# winform applications.
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Jan 23, 2009
If I use a single variable of type Excel.Worksheet to reference Worksheet1, and then change it to Worksheet2, Worksheet3 and so on, is it adequate to simply do "Marshal.FinalReleaseComObject(worksheetVariable)" once at the end? Or would I be left with some references still in memory? In other words, do I need to do a "Marshal.FinalReleaseComObject" before each re-assignment?
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Feb 3, 2010
I have a theory that the CLR garbage collection mechanism means that I can get away with circular references in my object hierarchy without creating deadlocks for teardown and garbage collection. Is this a safe assumption to make? (Target language VB.NET)
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Jul 30, 2009
Dim x as whatever
Try
x = new whatever(1)
something is done with x
[code]....
What happens to x = whatever(1)Does garbage collection find the pointer to the first new and destroy it or what?
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Oct 25, 2010
with VB.NET + MySQL i am having a connection object which is public public MYcnn as MySql.Data.MySqlClient.MySqlConnection when my main form opens MYcnn will open & will be available for all the procedures & functions. i never close this connection until the last form of the application closes (yes of course i compromise of some security + performance issues)
my problems is(1)when & how the garbage collector works to collect my connection object if my connection object remains open for > then certain time(2) how to offer or fix the time of my connection object availableness to garbage collector (3) i would like to write an event for the connection object closed event(i am explicitly declaring the connection object)
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Jun 14, 2009
i'm developing a simple 3D Cad Application that renders some created objects. I'm able to apply a color-based material to the objects but not to cover their surface with a texture, such as a bitmap. These are the two main code blocks of my application:
This code, creates the objects and creates materials for them. (To draw the objects, i'm using the Mesh class' methods):
objects(0) = Mesh.Box(device, obj.SizeX, obj.SizeY, obj.SizeZ)
materials(0) = New Material
materials(0).Diffuse = obj.Material
materials(0).Specular = Color.LightGray
materials(0).SpecularSharpness = 15.0F
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Jun 8, 2009
I would like to create a group/collection/set of unfinished rows that I can later add to a datatable.I have tried to do this by creating a DataRowCollection, and then create a new row based on the table I want then add it to the collection. Doing that I get a NullReferenceException though.Using the new keyword for dr does not work.[code]......
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Jul 23, 2009
I have a Collection, the keys are strings and the values are Collections. In the sub Collections the keys are strings and values are Singles/Floats. How would I loop through all of the data? I need to get the keys and values not just the values. I've tried this but it produces a cast error:
[Code]...
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May 9, 2009
Im using buttons from A to Z in a toolstrip which I need to capture the text property of the button which trigger click event. I do it this way which took a long coding to mention all buttons (A-Z) click events.
vb Private Sub az_btn(ByVal sender As Object, ByVal e As System.EventArgs) Handles A_ToolStripButton.Click, B_ToolStripButton.Click ... Z_ToolStripButton.Click
'shows text property of the clicked button
MessageBox.Show(sender.ToString)
End Sub
is there any efficient way to do this?
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Jun 2, 2011
I tried this
vb
Dim matches As String() = Regex.Matches(tmpFieldContent, strEmail).Cast(Of Match)().ToArray()
But it didn't work, as vb says
'Cast' is not a member of System.Text.RegularExpressions.MatchCollection'.
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Jul 1, 2009
I often use a for/next loop to cycle through a collection to find a particular member of that collection based on some criteria. This works fine in every case except one: when I want to then erase the very member of the collection I just found. For example, if I wanted to give the heave-ho to every obect in a collection class that has a member veriable Color equal to Red:
[Code]...
The problem is once the collection class member is erased it makes to loop invalid because taking out the member reduces the total count of the collection in the middle of the loop. Eventually I get a "Index is out of range" error.This circumstance has bothered me every so often; I bet more experienced programmers have a different type of loop system that works better than this when you want to erase a collection member.
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Apr 26, 2010
I am populating a collection from some tables in the database which serves as a look-up from controls (combobox) I am using but what I want is rather than hitting the database each time can I just cache the collection and get the collection from the cache? The look-up table may or may not change all the time so I would want to have a way to validate if the cached collection is still valid or not.
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Jul 23, 2009
I have created football (American) play creator. When the user is satisfied with a play he has created it is saved it as a file with a .play extension. What I want to do is to cycle through all the files in a folder (probably named after the team), and place each one that has the .play extension into a CList (of ClPlay) collection.I have been able to successfully load one play at a time by using this code...
Dim fs As Stream = New FileStream(diaOpenPlay.FileName, FileMode.Open)
Dim bf As Runtime.Serialization.Formatters.Binary.BinaryFormatter = New Runtime.Serialization.Formatters.Binary.BinaryFormatter()
Dim Play As CLPlay
Play = CType(bf.Deserialize(fs), CLPlay)
...but that was when a specific play was selected from a load dialog box. This time I want to load all the plays in a folder and store it in a collection, and I'm not sure how to modify the above code to do that.
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Jul 22, 2009
This I'm almost certain is an easy problem for those with more experience than me. I just need a routine that trades the places of 2 members of a collection class.
For example: If there are 5 objects stored in a CList of() collection class, I want to swap item # 3 and #5 (or any pair of indexes), what would be the code?
This simple problem has my head spinning because once you remove a member all the indexes change.
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Mar 2, 2010
I am trying to make a collection of controls that I can loop through. So I have this code in my form... Dim WizardFrameCollection As New Control.ControlCollection(Nothing)
I then try to add controls to the collection by I get a error "Object reference not set to an instance of an object." WizardFrameCollection.Add(Me.GroupBox1) I am not sure why I am getting this error. Groupbox1 is a groupbox that is on the form.
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Jul 30, 2009
I am using a collection to store data from a text file which I am letting the user load and I am using the .split to split and sort the data into alphabetical order and remove repeating words.However, I am having a problem removing unwanted characters from the final array. For Example, "This is the text file that I want sorted. It is random text not yet sorted"
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Nov 25, 2009
How can I make a comboxbox list the first item in the collection by default in other words i have a collection list
1
2
3
4
5
When program loads I want combobox to load 1
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Mar 9, 2012
I've heard that the c# garbage collector can be 'more aggressive' than it's vb.net counterpart. Is this true? Are there any other differences in how garbage collection is run in vb.net vs. c#?
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Jun 15, 2009
I'm trying to introduce delay to my code so that it would read in the noise or garbage data.
I'm receiving the data from RFID to pic thru RS232.Is there any simple delay that i can use? I seriously don't understand threading.
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Dec 4, 2010
I have a function like the following: Public Function testFunction(ByVal input_string As String) As String
[Code]...
or just let the garbage collector do the job for us? Both the above functions work, but I want only know the best practice for performance...
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Mar 2, 2010
I'm using following code to receive content of a ListBox
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Jun 6, 2012
I am using vb.net 3.5 and application is interacting with VC++ dll.
code is:
Public Delegate Sub delProcess() //Globaly declare
im del As New delProcess(AddressOf Process) //Process is function which not returning
[code].....
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