Unable To Find What Triggers System.NullReferenceException
Jul 1, 2009
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]...
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 studying and now working with Visual Studio 2008 Professional Edition. I am working on my project regarding "Serialization". I wanna to start my working with "System.Runtime.Serialization.Formatters.Binary" namespace because i am working on serialization project. I know by default IDE dosen't import it. So i went to add it in my project at "Add reference dialog" but i still unable to find out this namespace.
I use the following code in a Sub called "updateDb" to accept changes back to the Db, etc. in the .CellEndEdit event from a DataGridView:
Try ' Write changes back to actual .mdb file ' Accept changes from DataGridView object Me.Validate()
[code]....
Which is the most appropriate event to handle for this task? Right now I'm calling the updatedDb sub when the .CellEndEdit event triggers and when the .UserAddedRows event triggers.
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?
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 ?
i 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
i 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")
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)
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
I 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
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:
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]......
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.
I'm converting another project from VS2003 to VS2010 and am getting this message in the Immediate Window before I hit my MyBase.Load. From the warning, it looks like somting is undefined yet is being used - causing an exception. How can I trace this down?My app uses 2 DLLs, could the msg be coming from them during their load?
I have a text-boxes that use both the validating event as well as the lostfocus event.I have pinpointed the exception in the post title to the validating events.[code]Maybe I am unaware that CancelEventArgs are not suppose to be used in the validating event? [code]
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 have an InvalidCastException Error in my program. The program is that i try to insert an employee record into a database table after getting the details from a form. I've used Money data type is SQL Server for salary and SqlTypes.SqlDecimal data type in employee template class. i've used a stored procedure to pass the values and i add the basic value by passing a parameter by the method
Dim prm8 As SqlParameter = com.Parameters.Add("@basic", SqlDbType.Money) prm8.Direction = ParameterDirection.Input prm8.Value = emp.Bsc
I've used the money datatype itself even in the stored procedure variable.I get the following error.
failed to convert parameter value from sql decimal to decimal Even if i use prm8.Value = Convert.ToDecimal(emp.Bsc)
I get an error Unable to cast object of type 'System.Data.SqlTypes.SqlDecimal' to type 'System.IConvertible'.
I am getting this error when I am tring to load string type to data table)
Using connection As New SqlConnection("connectionstring;") connection.Open() Using Command As New SqlCommand("SELECT ClientId,forename,surname from t_clientdetails
