I am having a weird problem. IIf is messing up when I am working with an array. Apparently it is checking my else statement even though it isn't activated. Here is some code that demonstrates the issue:[code]
View 2 RepliesIn Perl (and other languages) a conditional ternary operator can be expressed like this:my $foo = $bar = $buz ? $cat : $dog;Is there a similar operator in VB.NET?
View 2 RepliesI saw this in some vb.net source code:Dim sTest As String = "" & drTest("column")
I was told that if drTest("column") is nothing, then sTest will be assigned "", so it is in effect doing:
Dim sTest As String = If("",Nothing,drTest("column"))What is the downside of doing it the first way I showed?
What is the difference between using If and IIf?
I am looking to make this statement work in a VB.net page:
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The ternary operator is causing a error: Compiler Error Message: BC36637: The '?' character cannot be used here. I want to use a tenary operator to display text based on the the field Inactive containing a true or false text value.
I'm usually reasonably good at translating C# into VB, but I'm a bit stuck partially due to the ternary operator in this function and also because I don't fully understand what is happening with the "from x in dataSource.OfType<object>() select 1).Sum()"
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Lambda expression with ternary operator in VB?
View 15 RepliesI'm having problems with a Nullable DateTime in VB.NET (VS 2010).
Method 1
If String.IsNullOrEmpty(LastCalibrationDateTextBox.Text) Then
gauge.LastCalibrationDate = Nothing
[code].....
Suppose we have a nullable value in vb.net: Dim i as Integer? We want to assign a value to it, basing on a condition, and using a ternary operator, because it's so neat and stuff: i = If(condition(), Nothing, 42) That is, if a condition is true, employ the null-ability, otherwise the value. At which point the shooting occurs. For no apparent reason VB compiler decides that the common base type for Nothing and Integer is Integer, at which point it silently translates the statement to: [Code]
View 5 Repliesdim val1 As Integer? = If(5 > 2, Nothing, 43)' val1 = 0 dim val1 As Integer? = If(5 > 2, Nothing, Nothing)' val1 = Nothing What gives? Is this a bug, or am I overlooking something?
View 1 RepliesThe following compiles in VB.NET (with Option Strict On) and outputs False:[code]Why does that work?The documentation clearly states that the three-argument version of If requires a Boolean as the first parameter:[code]So, why does this work? Is it a bug (or "hidden feature") in the compiler or is it a bug in the documentation and Boolean? is actually a valid type for the first argument of If(a, b, c)?In C#, b ? x : y does not compile if b is of type bool?.I've reported this issue to Microsoft Connect. Someone from MS has replied and confirmed that the documentation will be updated to include the Boolean? case.
View 4 RepliesIf you assign a value to a nullable integer via a ternary operator, it can't become null..While this question may seem like a duplicate of many, it is actually being asked for a specific reason.Take this code, for example: Dim n As Integer? = If(True, Nothing, 1) In that code, the ternary expression should be returning Nothing, but it's setting n to 0. If this were C#, I could say default(int?) and it would work perfectly. Now it looks like I am going to have to ditch the ternary and use a regular If block, but I really want to use the ternary. If Nothing were truly VB.NET's equivalent to C#'s default, how can you explain this behavior?
View 1 Repliesi have about 20 possible exception messages that i want thrown when an error occurs.i need somthng like this when catching the exception
Try
' do domthing
Catch ex As CustomInvalidArgumentException
'do domthing
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do i have to create a class that inherits from Exception for each type of exception?
catch an exception and then throw another exception? Like so:
Try
' Do operation xxx
Catch ex As Exception
' Operation xxx failed, need to execute cleanup
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The reason for doing this is that while I catch my exception on a higher level logic (to make sure I can log it properly), I need to do some actions in the event of the exception that I can only do inside my class/function.
I have the following code:
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I thought at first that because during testing GetFormsByStatus() returns 0 results maybe that was causing problems, but it doesn't make sense that Except() wouldn't work if the provided list had 0 items.
I have the following code:
Public Shared Function GetAvailableManufacturers() As List(Of Manufacturer)
'first get all the live orders and extract their mfrs'
Dim sos As List(Of OrderForm) = GetFormsByStatus(StockStatus.Building)
Dim unavailableMfrs As New List(Of Manufacturer)
[code]....
My idea to get available manufacturers was to get a list of all the manufacturers in my open forms, then get a list of all manufacturers and exclude all the manufacturers in the first list, illustrated like so (pseudo):
List A: {1,2,3,4,5,6,7,8,9,10}
List B: {5,7,10}
Result: {1,2,3,4,6,8,9}
I have set up my Manufacturer class according to this article so that it can be compared, but I'm still getting this error:
Unable to cast object of type '<ExceptIterator>d__92'1[csCore.Manufacturer]' to type 'System.Collections.Generic.List'1[csCore.Manufacturer]'.
I thought at first that because during testing GetFormsByStatus() returns 0 results maybe that was causing problems, but it doesn't make sense that Except() wouldn't work if the provided list had 0 items.
The following sub is throwing a"Object reference not set to an instance of an object."
exception.
For Each element As Song In modFiles.getSongs()
Dim col(2) As String
[code].....
I'm throwing an exception that looks like this...
View 3 RepliesI am trying to make a very simple aspx page that pulls some data from a mysql database.
The page builds without a problem. (the aspx contains just the default form and a div just to print some data)
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I am getting an exception when running the following code.
Public Function getSongs() As Song()
' Dim dir As New DirectoryInfo(Application.ExecutablePath)
Dim dir As New DirectoryInfo(directory)
[Code].....
I get an uncaught exception that says:
"Object reference not set to an instance of an object."
The song object has a:
Public Sub new(By Val filename as String)
... sub that sets a variable and retrieves file info (this code works)
I have a problem with running CLR profiler. It throws an exception: See the end of this message for details on invoking just-in-time (JIT) debugging instead of this dialog box.
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I started out with a console application but half way I switched to windows form in the application properties. Does that have something to do with it? I do this because I don't want to show the console. My application takes about 57 miliseconds to run. Maybe it's too fast for the clr profiler ?
Imports Excel = Microsoft.Office.Interop.Excel
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
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I am trying to get the type of a class by calling Type.GetType(), however it is throwing an null reference exception. I'm supplying the fully qualified name of the class as a string, I'm not sure what I am doing wrong. Here is what I am doing:Type.GetType("The.Name.Space.TheClassName")That is the fully qualified name of the class, it works fine for import statements.
View 2 Repliesi did this Dim strUser As String = txtacno.Text cmd1 = New OleDbCommand("Select * from BookDetails Where AccountNo =@acno and MemberId=@memid", con)
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the select query that i used in the above code,i have use and in it;so is this a valid sql statement?
I have written a small application perform CRUD operations on a Designations table. User search a Designation by Index and can make changes and the updates. I cannot see anything incorrect in my SQL and SQL works perfectly fine. Since i've created my Dataset using the desiner it automaticaly added the Optimistic concurrecy handling to the Dataset, therefore if an update fails it shold throw the DB conccurency exception.That's where the problem is, it doesnt throw the exception, application can retreive can update also fails to update on conccurency violation but when it happense it doesnt show the exception..... since code is long and have BLL and Presentations layers i've added a link you should be able downlaod the code + DB...
View 1 RepliesI am writing a parsing method for a csv record and want to throw an exception if the number of fields in the record do not match the expected length
View 3 RepliesI have a class as below in VB.NET. The issue is class calling itself. So vb.NET throwing Stock Overflow exception. But the same class is working fine in VB6 version of code in VB6.How to resolve this issue?
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I am trying to convert one of my unix text files to a dos text file. I am using the following command:
Shell(string.format("unix2dos {0}", sFileCompletePath))
I've already added the unix2dos command in my environment path on the server.But when I execute the above mentioned command I get a FileNotFound exception even when the file is located on the disk.
I'm doing a uni assignment and my application has to go to a specific folder and locate a file for data.The folder has 300+ files in it with a specific format for the naming of the files ie. the program goes to the folder looking for one specific file that has been derived from a different function and user input in the form.The program works fine when the file that it is searching for is there, but I keep getting a FileNotFoundException whenever the file that it's looking for is not there.I don't want the application to throw an exception every time the file doesn't exist because the program needs to return back to the loop to see if the next file is there or not.And so the loop continues until it's found all data and loaded it all into an array.How can I do a check of the folder to search for the file, and if it's not there, go to the next step without throwing an exception?
View 2 Repliesim dr As DataRow = CType(Me.ProductBindingSource.Current, DataRowView).Rowbut I get the error saying:
View 15 RepliesI'm using EPPlus 2.9.0.1 with Visual Basic.I have a DataTable with 35 Rows and 4 Columns and the code below:[code]When method 'LoadFromDataTable' is called, I get an ArgumentException (Negative row and Columns numbers are not allowed). I don't have negative numbers in row or column numbers, as far I know.
View 1 Replies