dim 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 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'm having problems with a Nullable DateTime in VB.NET (VS 2010).
Method 1
If String.IsNullOrEmpty(LastCalibrationDateTextBox.Text) Then
gauge.LastCalibrationDate = Nothing
[code].....
The 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 RepliesSuppose 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 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:
[Code]...
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()"
[code]...
Lambda expression with ternary operator in VB?
View 15 RepliesI 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 Repliesive got some simple problem i cant understand how to solve.
str(1) is an array and integer(or double, tried both)
a(1) is an array and integer (or double, tried both)
a(1) = a(1) + 1
Label1.Text = str(1) + a
the big part is where i get: operator '+' is not defined for types 'integer' and '1-dimensional array of integer'.why do i get that message and what does it mean? how do i make the code do what i want?
this is for a BINGO game final project that I already turned in but this just bugged me that I could not get the sorting figured out. I am trying to get this to sort the random numbers in to columns under the correct letters but I keep getting the error Operator '>=' is not defined for types '1-dimensional array of Integer' and 'Integer' under the line:
[Code]...
This is giving me a headache. I have this link query here that grabs an ID
Dim mclassID = From x In db.SchoolClasses Where x.VisitDateID = _visitdateID Select x.ClassID And then later on I have this linq query
ViewData("Staff") = From t In db.Staffs Where t.ClassID = mclassID Select t
I've tried quite a few things but to no avail. I've attempted casting, converting, Is operand, etc.
Why does this give variable A the value of zero (instead of setting it to nothing)?Dim A as double? A=If(2<3, Nothing, 6)
View 11 RepliesI'm trying to assign a date object to nullable but my code error on CBDate1 = nullDate. The message indicates that I need to assign a value to a nullable. This is my first time using nullable[code\]...
View 9 RepliesI'm trying to assign a date object to nullable but my code error on CBDate1 = nullDate. The message indicates that I need to assign a value to a nullable. This is my first time using nullable.
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When using the If operator [URL] to assign a value to a System.Nullable object, if the result is Nothing (null), then 0 is assigned to the object. Example: 'Expected value is null (Nothing). Actual value assigned is 0. Dim x As System.Nullable(Of Integer) = If(1 = 0, 1, Nothing) If x is a nullable type, why is it being assigned the default integer type of 0. Shouldn't it receive a value of null?
View 2 RepliesSo I'm writing the equality operator overload (Operator =())for a custom object, and the resulting mess of If conditionals is just an eyesore. But so far, it seems like the only sane way to check the values to as to match the specific behavior of this object.
The rules are:Num1 is required, period, and both the left and right operands and must be equal for True. Else, False.Num2 is optional, but if specified, must be present for both the left and right operands, and must be equal for True. Else, False.Num3 is optional, but can only be specified if Num2 is also present. Else, False.Num3, if specified, must be present for both the left and right operands, and must be equal for True. Else, False.
[Code]..
I also know that I could cache elements of the checks into booleans and then use those to reduce the amount of text. But that seems like a waste of cycles just for code readability. So I wanted to know if the SO community had better thoughts on reorganizing it, just in case I'm being too verbose with my checks.
I am trying to understand why the two code samples behave differently. I always believed the If() function to mimic the If language feature. Or am I looking at a behavior of Nullable(Of Integer) that is causing this?
Sample #1:
If Not String.IsNullOrWhiteSpace(PC.SelectedValue) Then
Dim pcFilter1 As Integer? = CInt(PC.SelectedValue)
Else
[Code]....
I would expect the following vb.net function to return a value of Nothing, but instead its returning a value of 0.
[Code]...
I wonder if this is not possible dim mystring as string="1" dim myint As Nullable(Of Integer) myint=0 myint=mystring It crashes on the last line why is that? mystring is already integer (1) , i dont have to cast using cint, i thought. option strict off- if this cause the problem
View 7 RepliesI've been pulling my hair out over some unexpected behavior from nullable integers.If I set an Integer to Nothing, it becomes Nothing as expected. If I set an Integer? to a String that is Nothing, it becomes 0! Of course I get this whether I explicitly cast the String to Integer? or not.[code] Previously I had my code up here so without the explicit conversion to Integer? and everyone seemed to be fixated on/confused by that. There were a lot of suggestions that Option Strict On would catch this type of thing. However, this is actually a quirk of the string-to-integer conversion rules which predate nullable types, but still impact them.
View 2 RepliesI've tried these two blocks but it returns the same value. I do not describe more, I simply just show the code:
Dim f As Nullable(Of Integer)
If f = 1 Then
Console.WriteLine("Equal")
[Code]....
It works in C# correctly...
How can I create a nullable numeric optional parameter in VB.NET?
View 3 RepliesI have been developing in VB.net for a cople of years now. I really miss the increment and decrement operators for integers that I grew attached to while using Java and C#. I have seen posts explaining how to implement a custom operator for a class that I have written, but I have not seen any examples of how to do it for a basic type like Integer.[code]....
View 1 RepliesI am trying to convert a piece of C# code, and I ran it through a converter, and had to make some changes.I am now running into this error:
Operator '<<' is not defined for types 'Char' and 'Integer'
The code is:
a += CType(URL(k + 0) + (URL(k + 1) << 8) + (URL(k + 2) << 16) + (URL(k + 3) << 24), UInt32)
b += CType(URL(k + 4) + (URL(k + 5) << 8) + (URL(k + 6) << 16) + (URL(k + 7) << 24), UInt32)
c += CType(URL(k + 8) + (URL(k + 9) << 8) + (URL(k + 10) << 16) + (URL(k + 11) << 24), UInt32)
The error occurs on each of the (URL(...) << X)
I want to assign the value of the integer returned from the InStr method to a variable. So, If TextBox2.Text = "The Apple Pie" And TextBox1.Text = "App", I want the integer returned, which in this case would be 5, put into a variable, lets say its called 'VarString'.
So VarString (would) = 5.
[Code]...
Operator '+' is not defined for types '1-dimensional array of Byte' and 'Byte'.How would I change the assignment statement in the code below so that each indexed byte position gets assigned the converted integer value in the for loop?
Dim byteArray As Byte()
Property Data_Out() As Integer()
Get[code].....
I am trying to assign integer values to the items in 2 different list boxes called lstWorkshop and lstLocation. I then want the equation, intCost = intDays * intLodgingFee + intRegistrationFee, to be executed and the result to be displayed in a third listbox named lstCost. This is what I have so far, but whenever I run the program the value that always gets displayed is 0, which is obviously not correct.
Public Class frmWorkshopSelector
Dim intCost As Integer
Dim strTotalCost As String
[code]....