VB.NET 2010, Framework 3.5
Trying to figure out how to get the memory back after I'm done with a list of a custom object type. I know forcing the list out of scope will reallocate the memory it's using but I need a way of doing it pragmatically. Does anyone know how to do this?
Public Class List_Of_T_Test
Private MyTestClass As New List(Of TestClass)
Private Sub List_Of_T_Test_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
Const LIST_COUNT As Integer = 5000000
Dim Count As Integer = 0
MsgBox("Note 'PF usage' on Windows Task Manager 'before the 5m list' is created")
Do Until Count > LIST_COUNT ' 5 million iterations
MyTestClass.Add(New TestClass With {.Value1 = CStr(Count), .Value2 = CStr(Count + 1)})
Count = Count + 1
Loop
MsgBox("Note 'PF usage' on Windows Task Manager 'after the 5m list' was created")
DestroyMyTestClassList()
MsgBox("When flow arrives here, I need MyTestClass to be gone, all memory to have been reallocated, or close to where it was before the list was created")
End Sub
Private Sub DestroyMyTestClassList()
' Does anyone know what code to put here, code that would totally destroy
' the MyTestClass and the 5 million items in it, reallocate the memory used
' by the list Of(T) MyTestClass
' MyTestClass.Clear() ' Doesn't work ??
' MyTestClass = Nothing ' Doesn't work ?
End Sub
Public Class TestClass
Public Property Value1 As String
Public Property Value2 As String
End Class
End Class
I understand the idea of letting it go out of scope but I have to tell you, I tried Disposing the form, closing it etc and loading a separate form and the memory still didn't come back. I guess GC hadn't got around to its collection business or something. I'll have to watch the GC work a bit longer I guess
This feller by the name of Jods was curious as to why I wanted to do this programmatically. The type of work I'm doing, creating copious types of custom lists that will be very dynamic in nature, that I need a way to destroy them and rebuild them with certainty that the old stuff is gone. These apps run non-stop for weeks sometimes so . . I need to pay close attention to memory and whatnot.
If of any interest to anyone, see code below that seems to reallocate the memory from a list of objects
Public Class List_Of_T_Test
Private MyTestClass As New List(Of TestClass)
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Const LIST_COUNT As Integer = 5000000
Dim Count As Integer = 1
Do Until Count > LIST_COUNT ' 5 million iterations
MyTestClass.Add(New TestClass With {.Value1 = CStr(Count), .Value2 = CStr(Count + 1)})
Count = Count + 1
Loop
MsgBox(MyTestClass.Count.ToString)
End Sub
Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
' This seems to completely reallocate the memory, paste this into a form's code,
' add two buttons, click button1 once, or few times while watching the
' 'Windows Task Manager' PF Usage.
' Then Click button2 once and the memory spike levels off, it all comes back
MyTestClass = New List(Of TestClass)
GC.Collect() ' ?
End Sub
Private Class TestClass
Public Property Value1 As String
Public Property Value2 As String
End Class
End Class
