i have never learn to loop an groupbox or anything so i don't know what wrong but the compiler said "NullReferenceException was unhandle" and here is my code.
iNumberOfPassengers = CInt(txtAdult.Text)
gboPassengerDetails.Hide()
Dim gboNextPassenger(iNumberOfPassengers) As GroupBox
[Code].....
I got two form. form 1 i ask the user a number of guest form 2 i ask each guest their name, their age
i decide to make a loop base on the number of guest but then i got this error. NullReferenceException was unhandled how to solve this...i underline under my code
Private Sub btnBook_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnBook.Click iTest = CInt(txtChildren.Text Do Until (iCounter = iTest) And (bIsNextClicked = True) PassengersDetails(iCounter).ShowDialog() Loop End Sub
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]......
i have to create for loop that create each time a new GroupBox with new name and location this is not a homework.it is a personal Application to manage my information [code]i have to change the name of the first Dim in the loop each time , but i couldn't.
View 2 RepliesI have several textboxes in a winform, some of them are inside a groupbox. I tried to loop over all textboxes in my form:
For Each c As Control In Me.Controls
If c.GetType Is GetType(TextBox) Then
' Do something
[code].....
i have a sort of problem when i try to add some linklabels in my groupbox. I used this
Me.Controls.Add(Groupbox3)
Groupbox3.Controls.Add(FlowLayoutPanel)
I can only add 4 linklabels no matter how big is the groupbox, i tried autoscroll but nothing. How can i do to store minimum 20 linklabels in a groupbox? Here is the whole code i used:
Imports System.Net
Imports DevComponents.DotNetBar.Controls
Imports System.Windows.Forms[code]....
Is there any way, maybe with a specific reference to put a control that records what plays wmp activex and to save somewhere on your computer?
I'm currently taking a VB class and i'm having trouble running my program properly.[code]
View 3 RepliesActually this application will run on window start up. what i try to do is to delete the file for certain date. I ask the program to delete file if set date equal to now system date... i also ask the program to check if the file is exist or not. If the file is exists. the program run properly but if the file not exists then on windows start up. .NET framework unhandle problem come out [Code]
View 5 Repliesi want to show the item in the textbox when ever i click the selected row in
listview and click the edit buttonheres my code in edit button
dim ClientId as string
For Each sItem As ListViewItem In Lvlist.SelectedItems
ClientId = sItem.Text
[code].....
Here using VB .Net 2008. I seem to be having trouble getting group boxes to appear when I click a radio button.
For example:
CODE:
This indeed brings up the first radio button however I have other groupboxes underneath which with the same code will not appear when the radio button is checked.
Eg:
CODE:
The second groupbox does not appear and is directly behind the first groupbox. The Top code doesn't seem to be working either.
Makes the following statement about the code below:
**"The computer evaluates the loop condition in the Do...Loop statment to determine whether the loop instructions should be processed. In this case, the inputsales <> String.Empty condition compares the contenst of the input sales variable to the String.Empty value. As you know the String.Empty value represents a zero length, or empty, string if the inputsales variable is empty, the loop condition evaluates to True and the computer process the loop instructions. *If on the other hand the inputsales variable is not empty, the loop condition evaluates to false and the computer skips over the loop instructions.
Based on the code I think it is the opposite: ...that while the inputsales value is not empty it should evaluate to true and process the loop and if it is empty it should evaluate to false and skip the loop?
See below.
Option Explicit On
Option Strict On
Imports System.Globalization
[CODE]...
I am getting a NullReferenceException was unhandled error when i run my debugging in this part of my code:Dim x As Integer = Val(index.Chars(0))
View 7 RepliesThis never happened to me, and the less data one has (usually) the less you can say what happened.I am trying to write a simple query analyser. I randomly receive these kind of crashes:
[Code]...
The file specified above does not exist. The place where it crashes is wrapped with Try-End Try. Moreover, yes, I have the painting event set up but it should not concern it (or maybe it does?). I have to add that I use visual basic express edition. The error occurs ocasionally - sometimes when I'm lucky nothing happens, and when I'm not then I get this crash.
When I debug a program my IDE simply does not catch System.NullReferenceException - execution continues as if there were nothing wrong.Moreover, when I go to the menu Debug/Exceptions System.NullReferenceException is not even in the list(Common Language Runtime Exceptions).
I manually add it (there is the Add button) and I put a checkmark in the 'Thrown' and 'User unhandled' column - now IDE catches it, but after I re-load the project the situation re-appears - and NullReferenceException is not on the list again. What may be wrong?
Update:No, when I step through the code the execution does not continue but exits the current block of code (sub or function). There were no Try...Catch blocks and there is a message: A System.NullReferenceException occured in MSCorlib.dll... But why doesn't the debugger stop at this line?
How can I get a NullReferenceException in the following scenario?
Dim langs As IEnumerable(Of SomeCustomObject) = //some LINQ query
If langs Is Nothing Then Return Nothing
If langs.Count = 1 Then //NullReferenceException here
What am I missing here? Debug shows that langs is really just a LINQ queryresult without any results...
Okay after searching two listbox's on a form I am trying to put a number as a string in a label setup for that but keep exgetting a NullReferenceexception error on the label. Label being "shippingDataLabel.text".e is my code;
Public Class MainForm
Dim fifteenShipping As Integer = 15
Dim twentyShipping As Integer = 20
[code].....
I have a VB.NET solution that I just upgraded. It was originally in .NET 1.1, I upgraded to .NET 2.0 and verified that it would build and run correctly. Then I upgraded from 2.0 to 4.0. It is still building with no errors, but when I try to run I am getting a NullReferenceException in Global.asax.vb. The really weird thing is, the line that is throwing the exception is this:
Dim dt As System.Data.DataTable I am not trying to use the variable, just declare it. Further down a Function is called that returns a DataTable and sets the variable, but I don't even get to that line. It is throwing the NullReferenceException on the Dim line. Has anyone run across this before? Is this some issue with upgrading?
[Code]...
I did a Rebuild Solution before posting. This is a web application and the only files I see in the bin folder are the dll files I am referencing. I'm not sure what else I should clean up.
I've seen so many posts on this but I just don't understand how to fix it.
HTML
Me.txtDeletedItem.Text = objDeleteLog.Name
[b]Me.txtDeleteReason.Text = objDeleteLog.Code.Description[/b]
[code]....
vb
Imports System.Windows.Forms.HtmlDocument
Public Class test_vbdotnet
Private Sub runtime()
[Code].....
I want VB.NET to get access to the innerText and make a if statement out of it. But it always returns error. (see the comments for details.)
This is driving me slighty madder than i usually am. The thing thats bugging me is the EXACT same code works in a test project i did with an sdf database.See my comments in the code
vb Private Sub tbScan_KeyUp(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles tbScan.KeyUp
[Code]...
VB
Dimserial As New Processserial.StartInfo.FileName = "adb"serial.StartInfo.Arguments = "get-serialno"serial.StartInfo.UseShellExecute = Falseserial.StartInfo.RedirectStandardOutput =
[code].....
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?
I keep getting a NullReferenceException error on this UNZIP code:
Dim Sh As New Shell
Dim SF As Folder = Sh.NameSpace("C:\test.zip")
Dim DF As Folder = Sh.NameSpace("C:\test")
[Code]....
i checked to see if i had a test.zip file in my root dir...its there... i have shell32 referenced
I am trying to flatten a multi-dimensional array with ConvertAll but I can't get it to work:
Private Function Flatten(ByRef a As Object) As Object
Dim elements As Integer = 0
Dim size As Integer[code]...
Why does it throw NullReferenceException?
The following code causes a NullReferenceException
tStartParameter = String.Format(tStartParameter, tTo, tSubject)
tProcess = Process.Start(New ProcessStartInfo(tStartParameter) _
With {.UseShellExecute = True})
tProcess.WaitForExit()
[Code]....
causes this exception:
InvalidOperationException: No process is associated with this object.
I have the following code:
Dim getProspect = (From p In dbContext.IRF_Prospects _
Where p.url = prospect_url _
Select p).FirstOrDefault
[Code]....
When I execute it, it throws an object reference not set to an instance of an object error on getProspect.user_id. Why is it doing this? Shouldn't the fact that I'm verifying it exists using IsDBNull first keep this from happening?
As a test, my boss asked me to convert a (not very critical) ASP.NET site from 1.1 to 4.0. Well, it's not extremely difficult and things are going well so far. However, I've hit a small snag. I keep getting a NullReferenceException when I run this code:
Public Property PageTitle() As String
'===========================================================================
'Exposes the PageTitle property of the child control.
[Code]......
We have a property whose job is to look up a description. If the lookup fails it should show an empty string.
So we can code the property like this:
If foo.bar Is Not Nothing Then
Return foo.bar.Description
Else
[Code]....
But are there any problems (performance, purity, other?) with just catching and ignoring the error?
You sometimes read it's expensive to throw an exception but I am not sure whether the author means it's expensive to build in exceptions using the Throw keyword (which I am not doing) or whether he means it's expensive to allow exceptions to occur (as I would be doing).
I have made a tic tac toe board and when i go to debug the application i get a "NullReferenceException was unhandled".
this happens diring this part of the code:
Dim x As Integer = Val(index.Chars(0))
I am getting a NullReferenceException was unhandled error when i run my debugging in this part of my code: Dim x As Integer = Val(index.Chars(0))
what can i do so this will stop and my program will work?