Is there any sense to set custom object to null(Nothing in VB.NET) in the Dispose() method?Could this prevent memory leaks or it's useless?!Let's consider two examples:
public class Foo : IDisposable
{
private Bar bar; // standard custom .NET object
public Foo(Bar bar) {
[code]....
Use the "new" keyword to create an object instance & Check to determine if the object is null before calling the method. I'm reading text from a text file using the following [Code]
View 9 RepliesI have a class and method exposed to a client asp.net app. The class looks like
<DataContract()> _
Public Class Class1
Private v_string As String
Private v_integer As Integer
[code]....
The method is declared as
<OperationContract()> _
Function GetStuff(ByVal bar As Class1) As String
In the client code I create an instance of Class1 and set the values for v_string and v_integer, but using Wireshark to look at the xml being sent to the server only a value for v_string is being sent as part of Class1. I'm guessing this is because it considers the value of v_integer to be null/not set. Here is an example of the client code.
Dim MyService as New Service1.ServiceClient
Dim test as New Service1.Class1
test.P_integer = 1
[code]....
how different types are passed/used since Integer is a intergral type and String is a class, but can't seem to work out what to do to fix the problem.
Does calling the Dispose method on a Windows.Forms.Timer call it's Stop method? Or should I stop the timer before I dispose it?
View 5 RepliesI have an RDLC report that I am rendering directly to the Response Stream as PDF (rather than using the ReportViewer). In the code that renders the report, it's DataSource is bound to a List(Of ClassA) objects defined in a custom assembly. This seems to work for the most part. My problem is that I can't seem to handle the situation where a nested object is null. For example, given ClassA and ClassB (the nested object) defined as follows:
Public Class ClassA
Public Id As Integer
Public Name As String
[Code]....
the report displays "#Error" if TheNestedObject is null. If TheNestedObject is not null, it correctly displays the Name.
I am indifferent if you are a VB.NET or C# or other .NET developer. I have a FACTORY class like the following:
[Code]...
When is it appropriate to apply the dispose method to controls?For example in a form that has five group boxes, once the first group box is used to gather user entries and is no longer needed, is it worth it to apply the dispose method to the first group box? Is it needed for local variables, for example a StringBuilder used within a private function which is only used while the function is executing?
View 1 RepliesI was experimenting with ways to get rid of some memory leaks within my application the other day when I realized that I know virtually nothing about cleaning up my resources. I did some research, and hoped that just calling the .dispose() would solve all of my problems. We have a table in our database that contains about 65,000 records. Obviously when I fill my dataset from the dataadapter, the memory usage can get pretty high. When I called the dispose method on the dataset, I was surprised to find out that NONE of the memory got released.
View 3 RepliesI have Overloaded the Dispose method of System.Windows.Forms.Form Class in which I have written some extra code which I need to execute when object of Form Disposes. But when I create the object of Form in 'Using' statement, the 'End Using, statement do not execute my overloaded Dispose method. What should I do?
View 13 RepliesI have some code which gets child items for a menu via the GetChildren function which takes a list of menuData: Dim builtMenu As New List(Of MenuData)(_rawData.FindAll(Function(item) item.GroupingID = 0))
For Each menuData As MenuData In builtMenu
If menuData.Children IsNot Nothing Then
menuData.Children.AddRange(GetChildren(menuData))
End If
Next
If I check if menudata.children isnot nothing, it always is nothing because the GetChildren function is yet to run (providing the child items, which do exist). If I remove this check and just have this code:
Dim builtMenu As New List(Of MenuData)(_rawData.FindAll(Function(item) item.GroupingID = 0))
For Each menuData As MenuData In builtMenu
menuData.Children.AddRange(GetChildren(menuData))
Next
Then I am presented with a Object reference not set to an instance of an object error on menuData.Children.AddRange(GetChildren(menuData))
I have a class that has a destructor and a Dispose method (I also inherit IDisposable). Why is it that the only time my destructor gets called is when I call GC.Collect()?
View 2 RepliesI have 2 question, hope somebody give me an explanation: 1. Should a local variable call dispose method and set to nothing? 2. If some method have an arguments which it is a ByVal argument, it means a method create a new object? But If it is a ByRef argument, it means a method don't create a new object?
View 4 RepliesFrom my understanding, .Net will pool SqlConnection objects where the Connection String is the same by default. Will the connection still be pooled if I call the Dispose method? This question is asked under the context of an ASP .Net application that at times makes many hits to the database in a single PageLoad event. I want the connections to be pooled, but would like confirmation that Closing and Disposing of the connection once the data operation is complete does not interfere with .Net's handling of the connection pool.
View 3 Replies<System.Diagnostics.DebuggerNonUserCode()> _
Protected Overrides Sub Dispose(ByVal disposing As Boolean)
Try
[code].....
From code analysis (Visual studio), I got this warning:
[Code]...
The warning disappear but then the literal control isn't anymore being displayed on the page... EDIT Note that the code come from a Microsoft web page: [URL]
I have following code (obtained from online tutorial). The code is working but I suspect the way to dispose the Excel com object is somewhat not proper. Do we need really need to call GC.Collect? Or what is the best way to dispose this Excel com object?
Public Sub t1()
Dim oExcel As New Excel.Application
Dim oBook As Excel.Workbook = oExcel.Workbooks.Open(TextBox2.Text)[code]............
I have a custom settings file that I designed using the designer. In my form, I have a function that creates a new instance of this settings by using a dim statement. Then I add this new settings object to a hashtable. After I exit this function, I no longer have access to the settings object without using the hashtable to retrieve it. If I want to remove the object from the hashtable, I can do a simple remove but the settings object still exists somewhere in memory. How can I dispose of this object as well since it inherits from ApplicationSettingsBase and does not have a built in Dispose() function?
View 5 RepliesI am getting the following Exception when calling MyBase.Dispose ()ObjectDisposedException was unhandled.I tried adding a Try Catch around the call but it doesn't catch the exception.
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing Then
If Not (components Is Nothing) Then
components.Dispose()
[code]....
FYI: The value of disposing is False
I'm playing an audio file like so:
VB.NET Dim audio As New Audio(Application.StartupPath & "est.wav", True) audio.Balance = 10000 audio.Play()
Which works great. But if I need to change that file, I get an UnauthorizedException because the I haven't disposed of it. But, if I add a dispose after .Play, it won't play.
I am making use of a 3rd party dll and am encountering some strange behavior in VB, which doesn't occur in C# Perhaps someone can explain what is going on. Anyhow, I am making use of a method in this 3rd party library which accepts an array parameter ByRef. The end result is the variable should remain null after the method call, but it is returning initialized for some reason.
[Code]...
Currently working on the status bar for application. I would like the status bar to display message errors if a user makes an invalid entry. I have a module which contains the main procedure and procedures to change the text property of my status bar. A Call is made to the procedures from one of the forms that requires the user input. The application compliles but I get an unhandled exception of type 'System.Null ReferenceException' Object reference not set to an instance of an object. [Code]
View 4 RepliesI looked at the Dispose() method in System.Data.SqlClient.SqlTransaction (using a decompiler):
[Code]....
Why does everyone say in forums that it is Rolling back in the dispose? Where does it rollback?
I have created a custom user control (JCUserControl), and I am using it in the Main Window. And my Main Window has no codebehind. I have this in the JCUserControl codebehind:
Private Sub ImmediateRadioButton_Checked(sender As System.Object, e As System.Windows.RoutedEventArgs) Handles ImmediateRadioButton.Checked
SomeTextBox.IsEnabled = False
End Sub
When I run it, it fails with the NullReferenceException. If I comment out the SomeTextBox.IsEnabled = false, it runs without any problems.
Edit: Found out that I could just check if the radio buttons are loaded before doing whatever I want to do.
Private Sub ImmediateRadioButton_Checked(sender As System.Object, e As System.Windows.RoutedEventArgs) Handles ImmediateRadioButton.Checked
If ImmediateRadioButton.IsLoaded Then
SomeTextBox.IsEnabled = False
End If
End Sub
Take the below example. I would expect the IsInterned method to return null, because this string can't possibly be in the intern pool having started up the test app for the first time? I would also expect, that if I did something like string.intern("this112233StringCan'tPossiblyBeInTheInternPool!£$%") first, then this would legitimately be returned by IsInterned from the pool. I've also done the same in c# and the behaviour is the same.
Whenever I use strings in code, I tend to do something like textbox.text = string.intern("someValue") etc or if (textbox.text = "someValue") etc. Infact, whever strings are being used, I've gotten in to the habbit of using string.intern. Is this a bad habbit rather than using constants or the resources file?
[Code]...
I'm converting a system of numerous programs from foxpro/foxweb/javascript to asp.net/vb/sql server.
I'm coding for a dropdownlist which is currently controlled via js.
I don't like using the control this particular way, but I want to maintain look and feel for the customer.
The control is initialized with some values via Page_Load() in behind code.[code]...
We have a huge windows application with poor exception handling. The application throw object reference error from lot of places and the system error message is showing to users as it is using message boxes.
I am looking for a simple solution which can be used to replace this message to something user friendly for the entire application
I am getting following error whenever I want to use IIf function inside entity framework query.
LINQ to Entities does not recognize the method 'System.Object IIf(Boolean, System.Object, System.Object)' method, and this method cannot be translated into a store expression.
vb.net 2005
Here is one attempt:
Dim myRow As BurnerService.OEBSContractBatchesRow
Dim myDate As Nullable(Of DateTime)
myRow = Me.BurnerService.OEBSContractBatches.AddOEBSContractBatchesRow( _
[Code].....
I have already defined in my SELECT statement in TableAdapter to tell it what to do if the parameters are Null:
SELECT a.ID, a.NameID, b.BNameID
FROM a INNER JOIN b
ON a.ID = b.ID
WHERE ((@NameID IS NULL) OR (a.NameID = @NameID))
AND ((@BNameID IS NULL) OR (b.BNameID = @BNameID))
I'm trying to search a generic list of 'User' business objects which has a property called 'Username': If (From u In colUsers Select u.Username Where Username.Equals(strUsername)).Count > 0 ThenI keep getting:Delegate to an instance method cannot have null 'this'.
View 16 Replies