Possible Duplicates: Coalesce operator and Conditional operator in VB.NET Is there a VB.NET equivalent for C#'s ?? operator? Is there a built-in VB.NET equivalent to the C# null coalescing operator?
View 4 Repliesi'm afraid that this is a stupid question, but i must assume that i have programmed VB.Net too long and now can't figure out how to convert this C# null coalescing operator into VB.Net:
if( Convert.ToBoolean(ViewState[tp.UniqueID + "_Display"] ?? true) == false ){}
I know the IIF-Function but i'm not sure how to use it here and if it gives the correct result(in IIF both expressions are being evaluated). Please help to shed light on the dark.EDIT: if you want to see the source of this: forums.asp.net There you can see a solution that generates a Option Strict On disallows implicit conversions from 'Object' to 'Boolean' compiler exception.
I have a class Customer which contains the property Extensions which in turn contains the property Any. I tried to do: Dim room = If(customer.Extensions.Any.ElementAt(0).InnerText, Nothing) but it threw an error when it did not find an Extension element in the incoming xml. I thought it would return nothing once it saw that the first expression was Nothing. Do I have to do a multiple if statement in this case?
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 am tightening up my coding with the Option Strict set to ON. It has now produced alot of errors. An example of this is:
If AllocatedDGV.Rows(i).Cells("RoomNumber").Value = RoomsAvailableDGV.Rows(j).Cells("RoomName").Value Then
It gives me the following error: Option Strict On disallows operands of type Object for operator '='. Use the 'Is' operator to test for object identity.
I need to write an interface to get data to/from our data files.
We have a low level class that holds field values for each record read from the files.
This just holds two values, the value read from the file (DBValue) and the updated value that may need to be written back to the file (CurrentValue).
These values may be any of the standard value types (integer, date etc) or a string.
Either value (DBValue or CurrentValue) may be null if not defined.
I have written the class to manage this data which works fine while option strict is NOT on.
But we have an office policy of having option strict on all the time.
When I put option strict on, my object value comparisons fail with the error: "Option Strict On disallows operands of type Object for operator '='. Use the 'Is' operator to test for object identity."
Question, how should I change the following code to handle option strict on ...
This is all running on Visual Studio 2010
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Possible Duplicate: Is there a conditional ternary operator in VB.NET?
Can we use Coalesce operator(??) and conditional ternary operator(:) in VB.NET as in C#?
I want to perform equality comparison in VB.NET and cannot get it to work. Error: value of type Boolean can not be converted to System.Drawing.PointF
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I have a fairly simple piece of code:
Private _PurchaseDelivery as PurchaseDelivery
Protected Overrides Sub InsertItem(ByVal index As Integer, ByVal item As PurchaseDeliveryItem)
[Code]....
Which is inside a class which overrides a custom list base. The code is occassionaly throwing an unhandled exception, System.NullReferenceException, on this line when used in production:
If _PurchaseDelivery IsNot Nothing AndAlso _PurchaseDelivery.DefaultSKUBinID.HasValue Then
DeafultSKUBinID is declared as an Integer? (Nullable Int) in the PurchaseDelivery class. I cannot see what might be causing this error, why would this be returning an error?
How to check whether a column is null i use the following code but I got this error "Input string was not in a correct format."
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When I put a break point to the last if clause in the sub ("If (backOrder < 0) Then", see below) it runs until the break point, if I put the break point further below, I get the following error:
Cannot insert the value NULL into column 'OrderID', table 'WHM.dbo.OrderDetails'; column does not allow nulls. INSERT fails. The statement has been terminated.
I've discovered first hand that it only happens when prodqty is bigger then qtyOnStock, thus executing the if clause.
The code:
Private Sub NCOSubmit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles NCOSubmit.Click
Dim sqlText As String = ""
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I am trying to create a treeview in VB.net, the data has to be loaded from MSAccess 2010 database. When I try to run this program I get error : Argument Null Exception was unhandled, 'column' argument cannot be null and the program crashes. I have pasted the code as under:
Imports System.Data.OleDb
Public Class frmRating
Private Sub frmRating_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles
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I have some code which gets child items for a menu via the GetChildren function which takes a list of menuData: Dim builtMenu As New List(Of MenuData)(_rawData.FindAll(Function(item) item.GroupingID = 0))
For Each menuData As MenuData In builtMenu
If menuData.Children IsNot Nothing Then
menuData.Children.AddRange(GetChildren(menuData))
End If
Next
If I check if menudata.children isnot nothing, it always is nothing because the GetChildren function is yet to run (providing the child items, which do exist). If I remove this check and just have this code:
Dim builtMenu As New List(Of MenuData)(_rawData.FindAll(Function(item) item.GroupingID = 0))
For Each menuData As MenuData In builtMenu
menuData.Children.AddRange(GetChildren(menuData))
Next
Then I am presented with a Object reference not set to an instance of an object error on menuData.Children.AddRange(GetChildren(menuData))
What does the ! mean in the following code snippet?Availability is a table in an access database Family and Model are column headers in the table cmbFamily and cmbModel are combo boxes.
If Availability!family = cmbFamily.Text Then
cmbModel.Items.Add(Availability!model)
End If
add the models of as aircraft family to a combobox(cmbModel) using a selection from another combobox(cmbFamily).
whats do Or operator in Vb do when it is applied as follows eg
Dim returnValue As UInt32
Public Const RMA_VC_RET_NULL_PTR_PARAMETER = 1
returnValue = returnValue Or RMA_VC_RET_NULL_PTR_PARAMETER
what does the 3rd statement do?
Dim bteJustTheAddress As Byte bteJustTheAddress = RawData(2) And &H7F
RawData is a Byte Array and I know &H7F is the Hex 7F
came across this issue while converting a for loop in C# to VB.net I realized that the increment operators are not available in vb.net (++ and --)whereas i was able it do something like cnt +=1 .In VB, a STATEMENT cannot be just an EXPRESSION. why this doesn't work in the same way as it does in C#.
View 4 RepliesI want to know what is purpose of '' in vb ? I have this statement: frontDigitsToKeep 2 and I want to convert it to C#.
View 2 RepliesWhat scenarios would you consider operator overloading in .net?
View 5 RepliesI am trying to get data from my Access database using like operator. For example my ProducID contains NoteBook, Notes etc. Using like operator, I want to get them all shown if user types No etc.Like operator did not give any errors but it only shows record when I put full NoteBook (does not show for Notes offcourse)
View 2 Replieshow to use? operator Like in Bindigsource? for Exmaple :
BindingSource1.Filter=" Feild1 Like N'%" & TextBox1.text & "'%"
that Code is false,Becuse hase an error?
s it possible to use NOT IN operator in If Statement?i.e. If strPara NOT IN (strCompare1,strCompare2) then exit sub
View 17 RepliesIs there a ?: operator equivalent in .net? eg in java I can do:
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I'd like to be able to do similar in VB.NET.
I'm converting vb code to c#There is enum from telerik library:
namespace Telerik.Windows.Controls
{
// Summary:
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Error1Operator '&' is not defined for types 'String' and 'System.Exception'.L:\Programming\thingy\Mail.vb3720thingy
not much else i can think to add here but it's making it hard to work...i'm using it like...
Dim Temp As String = "Hello" & vbCrLf & "Hi Again"
I'm having an error on the red font ...it says operator '+' not defined for type dbnull and type dbnull [code]...
View 7 RepliesBy Using
dv.RowFilter = "Convert([OIMainID], 'System.String') Like '" & OIMainIDTextBox.Text & "%'""
i'm almost getting the result i want. What i want is an exact match in the filter so if the box only contain the number 1 to will only show rows with the number 1 and not return say 12 13 14 etc etc, and vice versa for other numbers.
Is there any way to pass in an operator in VB.NET? I'm looking to reduce my lines of code and for two functions there is literally only an operator that is different.For example, I have two functions, Darken and Lighten. I'd like to get to a single function with as little code as possible. The only difference are Greater Than and Less Than operators.
Function Darken(ByVal clr1 As Color, ByVal clr2 As Color) As Color
Dim newR = If(clr2.R < clr1.R, clr2.R, clr1.R)
Dim newG = If(clr2.G < clr1.G, clr2.G, clr1.G)
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how do i randomize the operator?? i mean i wan the operator occur to be in random .i have to rush out my miniproject on next wednesday so i do ask the problem i meet here
View 5 Repliesi want to check if datasets have changes and after that use msgbox (vbYesNoCancel) when program closes ,when i wrote this code it had error "Operator 'Or' is not defined for types 'System.Data.dataset' and Boolean"..[code]
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