NullReferenceException While Reading The Description Of The Event Log Using System.Management Class?
Jan 25, 2011
I am able to query/read the event log using VB.NET 2005 (Win XP). But still I have a problem reading the "Message" / "description" of the event log.I am getting a System.NullReferenceException while reading the "Message" / "Description" of the event log.Also when I use System.Diagnostics.EventLog and read all the Event on by one I am able to read the message/description of the event. This is the code:
Public Sub ReadEvent()
Dim iCount As Int16
Dim PastFourHours As Date = Date.Now.AddHours(-4)[code]......
I am able to query/read the "Application" event log using System.Management classes in VB.net 2005 (win xp)But I have problem reading the "Message" / "description" of my custom event log.I am getting a System.NullReferenceException{"Object reference not set to an instance of an object."} while reading the "Message" / "Description of the event log while it is reading the others properties.Also when I use System.Diagnostics.EventLog and read all the Events on by one I am able to read the message/description of my custom event log. Why is that the System.Management classes can't read the my custom event log messages while the System.Diagnostics.EventLog classes can read them.The reason I want to use System.Management classes is bcoz I can query my custom event log where as with System.Diagnostics.EventLog classes I have to read the whole event log.
I am attempting to use the System.Management.ManagementObjectSearcher class in VS 2005 (see below) but get a error message for both the ManagementObjectSearcher class and queryObj As ManagementObject - Type ManagementObjectfSearcher is not defined and Type ManagementObject is not defined. how do I use this class in Visual Studio 2005?
Dim searcher As New System.Management.ManagementObjectSearcher( _ "rootCIMV2", _ "SELECT * FROM Win32_ComputerSystemProduct")
2012-03-16 19:15:09Z E System.NullReferenceException: Object reference not set to an instance of an object. at System.Timers.Timer.set_Enabled(Boolean value) at System.Timers.Timer.Stop()
Here's the code:
Timer declared as private member variable. Private _myTimer As System.Timers.Timer Initialize timer method.
[code]....
The timer has to have a value or else the Timer.Stop() call would be throwing the exception. This is a sporadic error and I'm just trying to see if anyone has experienced this before or if anyone has any ideas of what could be causing it. It is occuring in a WinForms application in the event handler for the Elapsed event of the Timer, but it is only occuring sporadically on the users computer. I haven't been able to reproduce the error myself.
I am using VB Express 2008, and I'm experimenting with querying WMI. I have tried the code samples from MSDN, but they do not compile. Here is an example of code that my IDE doesn't like:
Imports System Imports System.Management Public Class Query_SelectQuery Public Overloads Shared Function _
[code]....
In this case, SelectQuery and ManagementObjectSearcher are underlined with squiggly blue, and it doesn't know what these are. What am I missing here? Please help, because I'd love to be able to write console apps that query WMI.
I know its unlikely but I was wondering if there is any way to get the comments (i.e. the bits after the ''') of a class or property..? I have managed to get a list of properties of a class using the PropertyInfo class but I cant find a way to get the comments / description.. I need it for a guide I am writing for the administrators of my site - it would be great if it could automatically update if new properties are added, so there is no need to worry about updating it in the future too much.
I once was able to insert a Class-Header type XML comment section which structured the describing of a class; I now cannot remember how I did it. I think I either used a snippet or some macro-type character combination that inserted some XML documentation fields which made commenting a class well structured. It may have even been an extension.
I'm trying to write some code that can read events from another computer's event log. I haven't used WMI or System.Management all that much before this, and despite all the examples I've found on the web (there's a lot), I cannot authenticate to another machine.
No matter how I tweak the code, I always receive a System.UnauthorizedAccessException in System.Management.dll. (The message is "Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))".) I have tried connecting to two different Vista machines on the network using their local user account information.[code]...
I want to learn by resolving a problem i have been having with my small car hire business.
I want to develop a system which will enable me manage the business efficiently, the solution should be able accessible to more than 1 users, on my LAN and i would also like to have a web reservation system.
How easy/difficult is this when using VB.Net and what things must i do at the onset to achieve my goal.
I am the beginner to .net framework itself.I am too confused whether to use asp.net using vb or just visual basic is enough?As I am just thinking over this topic.I feel this is not a website so not to go for asp.net.I thought to do it in
In this code, DirInfo.FullName is sometimes null. So I put this code inside a Try Catch. Although it works fine but I see a System.NullReferenceException in Immediate Windows. I just want to prevent it.
So tried:
If DirInfo.FullName IsNot Nothing Then Me.Tag = DirInfo.FullName
If DirInfo.FullName <> Nothing Then Me.Tag = DirInfo.FullName
If DirInfo.FullName <> "" Then Me.Tag = DirInfo.FullName
But I still get this System.NullReferenceException! How should I check DirInfo.FullName so I prevent this exception?
As the beginner I want to know Is it necessary to add MDI parent for Library management System?
Can this be done without MDI Parent too?
And also is it necessary to add the below code for mdi parent of every project? Private Sub ShowNewForm(ByVal sender As Object, ByVal e As EventArgs) ' Create a new instance of the child form.
I've been assigned to do some report analysis in a management information system.My question is, do you think it's a efficient way to gather datas from SQL, with the use of basic syntax and have them manipulated through my code in VB.NET?(I'm more skilled with this kind of execution, but it takes a lot of data calling from the database)Or should I just do the advance way of inner jointing or more likely a stored procedure?
I ran accross this piece of code that uses the System.Management to get the free space on a drive for ONLY logical drives on Hard disks drives. It does this by check the Mediatype. Anybody know where I can find a listing of the Mediatype values? I would like to modify this to get free space only from USB flash drives.
I have read a ton of stuff about this but not getting it, noob error I am sure
Type 'System.Management.ManagementObject' is not defined. Type 'System.Management.ManagementObjectCollection' is not defined. Type 'System.Management.ManagementClass' is not defined.
Function GetHtml(ByVal url As String, ByRef web As WebBrowser) As String
Dim WebString As String Dim myURI As New Uri(url) web.Url = myURI WebString = web.Document.Body.InnerHtml Return WebString End Function System.NullReferenceException
Any links to good descriptions and/or tutorials (with VB.net 2008) on OdbcDataReader? I tried, but didn't find many. MSDN is not such a good help in this case.
I'm pretty new to VB.NET (VS 2008) so I apologize in advance if my problem is very basic.
I have defined several public arrays with fixed dimension is a public class:
Code:
Now in the main class I'm declaring two global variables:
Code:
I can then redim "parent2.V()" without problem.
Everything works fine with "parent1" but "parent2" gives me a NullReferenceException when I try to read/write from it. Troubleshooting tips tell me "Use the 'new' keyword to create an object instance" which is what I did. How to declare that array "parent2"?
I'm looking at creating an asset management system for all our electrical equipment, the equipment already have security labels with barcodes on them. What I am wanting is to be able to do is create a form where i can state some general information about the piece of equipment and then scan a barcode to register the equipments security number. so that if an employee needs to use that piece of equipment off site then I can just scan the barcode and register that the employee has taken the equipment.
My understanding is that the barcode reader is generally plug and play and acts as an input device? So what I would need to do is find a way to identify which input device is used, and if it is the reader find a way to assign a labels text to the value that has been read, rather that insert it into a textbox? I also want to display the actual barcode itself above the label, so I assume I would need to re-generate the barcode as an image and then display the image?
Basically I am trying to create a child management system for a nurse using vb.net and SQL as my backend dbThe application consists of a number of differen forms. Two of these forms are called "frmSearchInfo" and "frmChildDetails".
frmSearchInfo consists of: - three textboxes "SFirstName" "SLastName" and "SDOB" - one button "BtnSend"
[code].....
When users enter details on form "frmSearchInfo" I want it to be able to search records in the database and return the same first name, second name and DOB as well as the ID, phone, addressline1, addressline2, county. I also want the datagrid to show dates of appointments for the children.The records needed are stored in the Child Table.
I have some software that does the following code to try to loop through the software (MSI's) that are installed on a machine. Originally it was passing in a package name as a parameter, but I've simplified my code to make it easier to follow. It was working before, I can't figure out why it's not now. Here's an example snippet with a package that doesn't exist:
I need to read the value of one subkey located under a list of 17,000 keys in windows registry. I have no problem doing it locally but cannot get the system.management name space to do the same remotely. I know MSDN documents the system.management name space but much more knowledge is assumed than in other areas I have used. Assume no problems with connection and authentication.[code]....
I have created a windows Service which invokes executables on remote machines, waits for it to complete and then proceeds to the next machine on the network.
The Account type for the windows Service is "Network Service". For monitoring if the process is completed on the remote machine, I am using ManagementEventWatcher class. I get the following error when I start the Management event watcher object.
I have a MyDataGridView.DataSource = MyDataSet.Table(0) and the AllowUserToAddRows = True Once the user have finished typing in the column zero I have to check if they didn't type invalid stuff. It have to be numeric and 4 chars long.
the code is:
Private Sub Result_CellEndEdit(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles Result.CellEndEdit If e.ColumnIndex = 0 Then
[code]....
And it is not all the time, but depending on how quick and stupid (i'm expecting stupid users, as usual) I click on the previous row or the AddNewRow row I get a the damn System.NullReferenceException on my If line:
If Not (IsNumeric(Result.Rows(e.RowIndex).Cells(0).Value) And Result.Rows(e.RowIndex).Cells(0).Value.ToString.Length = 4) Then I'm really not in the mood of just put a Try Catch, as it looks like bad programming in this case. I've already tried a couple variations with "is nothing" but no success?How could test it won't cause a Null exception before testing the row value?
