I'm trying to run a simple database and im getting a "System.NullReferenceException" error ) & "Additional Information:Object reference not set to an instance of a object" .
txtItemName.Text = rowCurrent.Item("ItemName") <-- highlighted in yellow
Code is as follows:
vb.net
Imports System.Data.OleDB
----------------------------------------------------
Public Class Form1
[code]....
I think its better if i attach my files for you understand what i wanted to happen in my program.
We are now in our finals and for our project we need to make a program that shows connection of database(sql or access) and vb.net so dont mind if it has a problem in design or anything bcoz the objective of this project is to show what we've learn in our subject IT Programming 1 (vb.net)
I dont know what to do in this part of my program. what to do first? why is it attaching zip files is not allowed?
I have been trying to figure out the source of error in my application. What this function (GetConcentrations()) is to display data from my database onto a DataGridView. The function is called in the PageLoad but works fine but when I call it in another Sub, I get this error.
Here is the code:
Private Sub GetConcentrations()
Dim conString As String = ConfigurationManager.ConnectionStrings("dbAsthmaConnectionString").ConnectionString
Me.dataAdapter = New SqlDataAdapter("Select * from tblConcentrations", conString)
[code]....
For i = 1 To 60
Me.Controls("picturebox" & i).BackColor = Color.White
Next
i want to change backcolor of picturebox but when i run program,i get this error :
An exception of type 'System.NullReferenceException' occurred in EZEE Restaurant.exe but was not handled in user code
Additional information: Object reference not set to an instance of an object.i go to Project->Add reference and then look for "System.NullReferenceException" but i don't find it.
Here are parts of my
Dim setting As My.MySettings
lvl As Integer
Dim xp As Integer
Dim xpt As Integer
[code]....
I have done the settings as type integer and set the values that I wanted but I get this error: A first chance exception of type 'System.NullReferenceException' occurred in Click Game concepts.exe
i am using VB.net 2003 and i am trying to get the number of rows of a dataset from form1 into form2 in order to use it for something else and i am getting the error"System.NullReferenceException occured...Additional information: object reference not set to an instance of an object"...my code is like this:in form1:Public x as integer= me.dataset.table.rows.count here it gives me the error
in form2:
dim frm as new form1
msgbox(frm.x)
I have recently gotten my hands on a free, open-source IMAP connection API.So far, I have been successful in creating a connection to one of my accounts.Where I'm getting stuck is retrieving folders and/or emails from those folders.Does there happen to be anyone here that is familiar with this API, or even Gmail (particularly the folder structure for IMAP)?
If not, here is a link to the DLL that is listed on sourceforge and the company's website that created it (if you feel like testing):
Koolwired
Sourceforge - Koolwired API
I have created a test account so feel free to use the code below without worrying about username/password issues; I'll just delete it when I'm done with it.Here is the code I have made so far for making a connection:
Dim gSession As New Koolwired.Imap.ImapConnect("imap.gmail.com", 993, True)
Dim gAuthenticate As New Koolwired.Imap.ImapAuthenticate(gSession, "imap_test@serysoft.com", "imap_test")
Try
[code]....
When I run that code, I get an error that states:System.NullReferenceException: Object reference not sent to an instance of an object. (The bold line in the above code).
Now, I'm not sure exactly what that means. Does that mean it tried to access the server and "INBOX" doesn't exist so it gets returned a NULL value? Or is it possibly the coding itself?Maybe the Gmail folder system is weird due to the fact they use labels (even though from what I have read online, the labels act as the folders in the IMAP system).
I'm getting System.NullReferenceException error when I try to add the employee info to the Employees list.
[Code]...
I got the following code from the demo code samples and just changed the textbox names. But it throws an error:
Private Sub Fill_TextBox()
Dim Num As Integer
Dim DSet As DataSet
[code]....
The error is:
System.NullReferenceException:Object reference not set to an instance of an object.
I am completely new to ASP.NET and VB as well as C#. I am trying to add customers to a contact list out of a DB. Then the list can be referenced to call them up. But when I try to run it I get System.NullReferenceException: Object reference not set to an instance of an object. In line 19.
Here is my code:Page 1 is default page...it connects to the database and grabs the contact information and allows me to select the current contact and add them to a listbox on a separate page:
Imports System.Data
Partial Class _Default
Inherits System.Web.UI.Page
[code]....
The error occurs on line 19 (For Each customerEntry As DictionaryEntry In Customer) in the second set of code from the default2 class.
I am coding in vb.net. At times the data is empty/null this is due to user's input into the db.i will like to bypass it, however i get no luck.here is snippet of my code:
If hct.mydbvalue.name IsNot Nothing Then
dr("mydbvalue") = hct.mydbvalue.name
End If
I still get an error: System.NullReferenceException: Object reference not set to an instance of an object.is there a way if it is a null value to not do anything?
Here is the stack trace:
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.
How to do a simple log in program in netbeans using java database ?
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View 8 RepliesI am trying to make a very simple program that connects to a MySQL database using VB.NET. My program only has one form and one label. I setup my MySQL database to have a table and one field (a VARCHAR)called "Tab1". I manually inserted the value "CLOSED" into the Tab1 field using PHPMyAdmin. I want my program to change the value of the field to OPEN/CLOSED and I also want the label text on my form to change too when it's clicked.
[Code]...
I want to create program in vb2008 express with ms access database. Can somebody help me so i can learn how to program using classes hard coded. I have learned vb6 before but it has a big difference on vb2008.
I have a database named "DATABASE" in ms access 2003 and the details are: Table :
EMPLOYEE(EmpNo, EmpName), DEPARTMENT(DeptID, DeptName), CATEGORY(CategoryID, CategoryName), SUPPLIER(SupplierID, SupplierName), ITEM(ItemID, Itemname), ITEMLIST(ItemListID, ItemID, ItemDescription), INVENTORY
[CODE]...
All the CAPITALIZED name are Table and all items inside the parenthesis are fieldnames. I don't know where to start on working on this RECORDS. I was able to understand visual basic 6 a bit, and i am trying to apply the coding to VB 2008 but all i get is errors. I am hopeless now and i need help to be able to start my programs. If someone can give me a sample code, i think i would be able to trace the line of code to be able to understand it. I am currently an inventory manager on the small company i was working with and i like to organize my record by using database.
I've got a little problem here:
Code:
Dim DirInfo As IO.DirectoryInfo = Nothing
... some code ...
Me.Tag = DirInfo.FullName
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?
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
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?
System.NullReferenceException was unhandled
Message=Object reference not set to an instance of an object.
Source=Image Invoice Management
[Code]......
i do understand that the list count is 0 so shouldn't it be declairing Start_Pos = 0
i have a code that grabs an image from a site, this works fine and it does get the image fine, but every now and again my internet runs slow and it takes a while for the image to pop up thus causing the error:[code]How would i make it display the msgbox if it returns NullReferenceException error ?
View 9 Repliesi have a small problem with my code that only happens every now and again.Im using multi threading on this and every now and again i get this error: System.NullReferenceException was unhandled Message="Object reference not set to an instance of an object."
Some times the program completes perfect with no errors and sometimes i get the above error.When i get the error there is always 1 item left in the list but when it completes perfect no items are left.Again this error does not appear every time, only every now and again. For example i had to run my program like 20 time to get this error, 19 times it worked perfect with no errors and 1 time with this error.
This is my first ever post in this wonderful forum. I am new to vb.net programming. Given below is a piece of code which throws a system null reference exception at the end of the loop. I am unable to figure out the problem. "drledger" is null at the end of the loop. Even though i am able to catch the exception what can be done to avoid the null reference exception.
Private Sub btnSalesExport_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSalesExport.Click
Dim iRowMax As Integer
[code]......
how to create a program that can access information held in an excel database and show it in a simple form.
View 2 Repliesi have this code in my btnsave..it can detect conflicts but after that a dialog box saying: An unhandled exception of type 'System.NullReferenceException' occurred in AppointmentSchedulingClient.exe
Additional information: Object reference not set to an instance of an object. and it points to the green one below.
If Val(cbostart.Text) > Val(cboend.Text) Or Val(cbostart.Text) = Val(cboend.Text) Then
MsgBox("Error in time.", MsgBoxStyle.Information, "MESSAGE")
[Code].....
I have a program that will print dwg and idw drawings to different printers. from our drawing vault we kan use a plotbutton which creates a pcf-file (text file) and copies the drawing to a specific location. the program reads the pcf file which contains the max printsize for the drawing, who is printing it, nr of copies, location of the drawing. all data is written to or read from a small database. as long as there are drawings the printing goes fine, they are listed in a datagridview on the form. As soon as the last record is removed from the datagridview I get the following error[code]...
View 2 RepliesI am in great trouble, I have a project on visual studio 2008 and I getting connectionstring using ConfigurationManager.ConnectionStrings("connestionstring") .ConnectionString. this project have a app.config file which contain
[code]...
I get this message each time I run the appA first chance exception of type 'System.NullReferenceException' occurred in <Applicaton>I have isolated the key Subs which seem to upset it, but I cannot for the life of me figure out what it is about it that's upsetting it. I have used On Error Goto etc for the time being, which gets around it but I would like to solve it rather than jumpver it.Err.Description returns "Object reference not set to an instance of an object."My sub looks like this:
View 2 RepliesI 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]......