I have a function that takes in a number of parameters.. it then does a db insert.i have a foreign key on one of the fields (modelID)i want to pass a NULL if no model ID is selected.[code]but now i get an error saying: Nullable object must have a value.if i pass in a 0, it does not insert because it breaks the DB constraints.
View 4 RepliesI have an update function that updates an sql server db table through a dataset. One of the fields in the table is an integer and accepts null values. So when I am populating the update function I need a way to enter a null in when the function wants an integer.
I tried to do it this way but _intDLocation = "" throws an exception
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I have a Function within a data access layer, which accept a number of parameters. Among these is a decimal value, but in some cases the decimal value with be NULL, here is the code from the function
I am using the following code in my code file to pass the value to the function...
Convert.ToDecimal(textbox1)
How can I pass a NULL value to my function?
I'm trying to write my very first "serious" program using a mysql database. I use the mysql connecter dll to connect with my database. I have a subject and a visit table. I can select a subject and I can get all the visits for all subjects in a list box with:
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My problem is that I have two forms, Form1 and Form2 ...on Form1 there is a TextBox called txtTotal (this contains the calculation of Ticket Prices, thus it's a numeric value) and on Form2 there is a TextBox called txtTotal2. All I want to do is get the same number that appears in txtTotal on Form1 to appear in txtTotal2 on Form2 .However whenever I try some of the help tips online such as using a declaring txtTotal as global or friend it dosn't work, and any other code iv tried attempts pass the textbox value as String which brings an error.
View 2 RepliesI have a field in a datatable (dt) that can be integer or NULL.
View 7 RepliesBasically, when you set an Integer to "Nothing" it seems to equal the same value as if you were to set it to 0. So, in a function that returns an Integer how can I return something that will show that the function failed? In most cases I would use -1 or something but in this case I need to allow for negative values too.
Here's some more detailed information: I'm using the GetValue method of the Microsoft.Win32.RegistryKey class to read a numeric value from the registry. The GetValue method has an optional argument that you can pass in that specifies what should be returned if the value did not exist, normally I would use Nothing but in this case because I am storing the returned value in an Integer then it is just the same as if the GetValue method returned 0 (which is a valid value in this case).
Example:
vb.net
Dim Reg As Microsoft.Win32.RegistryKey = My.Computer.Registry.LocalMachine
Dim SubKey As Microsoft.Win32.RegistryKey = Reg.OpenSubKey("SYSTEMCurrentControlSetControlTimeZoneInformation", False)
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I think this is a pretty basic question, but I just want to clarify. If I have a variable with a null value, and pass it as a parameter that is optional, will the parameter get the null value, or the default value?
dim str As String = "foo"
dim obj As Object
//call 1
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I have a function that accepts a String by reference:Function Foo(ByRef input As String)
If I call it like this:
Foo(Nothing)
I want it to do something different than if I call it like this:Dim myString As String = Nothing Foo(myString) Is it possible to detect this difference in the way the method is called in VB .NET?All the logic is in the second overload, but I want to perform a different branch of logic if Nothing was passed into the function than if a variable containing Nothing was passed in.
I have a function that returns a Datatable. I am passing a list of Integer as an argument. Then I thought tis would work.
Public Function GetEventsByEventType(ByVal EventType As List(Of Integer), ByVal DayInterval As Integer) As DataTable
Using con As New MySqlConnection(strCon)
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as you can see. I use string.join to convert the list of integer to something like this. '1,2,3'. Problem is that is read as a string so i get the incorrect results. I need to have where EventType IN(1,2,3).
i have a stored procedure to insert data into table create procedure insertdata
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i'm not 100% sure about sql server but i think it doesn't accept null value for date type columns but in oracle, a date column can accept a null value. and since i'm using oracle, this is causing some problems because in my form, a textbox item bound to a date column will not accept a null value. reading thru some threads, it would seem that it is not possible to pass a null value to a date type in .Net.
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If 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 getting System.NullReferenceException:Object reference not set to an instance of an objectwhile executing the below code..!!
Dim arr() As Integer
Dim g,j As Integer
g=10
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I have a class and method exposed to a client asp.net app. The class looks like
<DataContract()> _
Public Class Class1
Private v_string As String
Private v_integer As Integer
[code]....
The method is declared as
<OperationContract()> _
Function GetStuff(ByVal bar As Class1) As String
In the client code I create an instance of Class1 and set the values for v_string and v_integer, but using Wireshark to look at the xml being sent to the server only a value for v_string is being sent as part of Class1. I'm guessing this is because it considers the value of v_integer to be null/not set. Here is an example of the client code.
Dim MyService as New Service1.ServiceClient
Dim test as New Service1.Class1
test.P_integer = 1
[code]....
how different types are passed/used since Integer is a intergral type and String is a class, but can't seem to work out what to do to fix the problem.
I am making use of a 3rd party dll and am encountering some strange behavior in VB, which doesn't occur in C# Perhaps someone can explain what is going on. Anyhow, I am making use of a method in this 3rd party library which accepts an array parameter ByRef. The end result is the variable should remain null after the method call, but it is returning initialized for some reason.
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I'm having problems with marshaling in VB.NET to C++, here's the code :
In the C++ DLL :
struct APP_PARAM
{
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I am creating a dll with all the functions and subroutines that I use all the time and I decided to create a function that I can pass different types of array to so the function obviously (or not) would have an array of type object. Now I no you can pass any type into an object type but when I pass an integer array into an object array I get an error.
value of type '1-dimensional array of integer' cannot be converted to '1-dimensional array of object' because 'integer' is not a reference type.
Shared Function CompareArray(ByVal FirstArray() As Object, ByVal SecondArray() As Object, Optional ByRef ErrorMessage As String = "") As Boolean
Dim IntArrayOne() As Integer = {1,2,3,4,5} Dim IntArrayTwo() As Integer = {1,2,3,5,6} Dim IsSame As Boolean = False IsSame = CompareArray(IntArrayOne(), IntArrayTwo())
ive 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?
I faced an error when upgrading VB6 code to VB.NET. The error occurs at AddressOf WindowProc
AddressOf expression cannot be converted to 'Integer' because 'Integer' is not a delegate type
My declaration for SetWindowLong is:
Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA"(
ByVal hWnd As Integer,
ByVal nIndex As Integer,[code]....
What is the reason for the error I get?
I'm trying to create a linked list of an array of integers. Why is the following implicit conversion required?
When I run the code that contains that conversion, I get the following error.
As a real-time data acquisition user control data (a packet of an array of bytes) arrives every second, is converted into an integer array and inserted into a linked list.
The most recently arrived data is painted as coordinates on a grid at the right of a PictureBox using Graphics.DrawLine (pen,X1,Y1,X2,Y2).
The oldest data (arriving 120 seconds ago) will be drawn at the leftmost portion of the Picturebox.
Why a linked list rather than a list? To display 120 views of time sequence data, the draw routine the most recently inserted node to a node that points to Nothing. How do I limit the length of the linked list to 120 nodes and always ensure that the last node points to Nothing?
Do While Not item Is Nothing
item = item.NextItem
Loop
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?
I am a newbie in VB and I got a piece of code which can display the current running program. I need to use that in VB2005 and I got the below error message. Can anyone help how to fix it?[code]
View 18 RepliesI'm trying to convert a VB6 project to .NET, but I get problems with some callback functions, and the following message comes up: "AddressOf' expression cannot be converted to 'integer' because integer is not a delegate type" I've seen several solutions to similar problems like this, but I am not able to understand this issue with delegates.
After the conversion, the code look like this:
Declare Function vsmsgwSetDataPackageCB Lib "vsmsgwW.dll" (ByVal PACKAGE As Integer, ByRef arg As Integer) As Integer
Dim arginitP As Integer
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Which gives the error: Method 'Public Function PackageCB(HisNodeID As Integer, ByRef data() As Byte, ByVal length As Integer, ByRef arg As Integer) As Integer' does not have the same signature as delegate 'Delegate Function DelegatePackageCallback(hwnd As Integer, lparam As Integer) As Integer
I have a LINQ2Entity problem, I want to get the value, string, from a database, so I select FProducts.Serial_number, and to end the query, I do .ToDictionary. The problem is, it tells me that it doesn't have sufficient parameters, to convert ToDictionary. So I need something like select FProducts.Serial_number, Nothing). ToDictionary. Also FProducts.Serial_number, 0).ToDictionary doesn't work.
Sub GetStatistics(ByVal ProductNumbers As List(Of String), ByRef Passed As Integer, ByRef FailedProducts As List(Of String))
Passed = 0
FailedProducts = Nothing
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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:
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I am new to EF Linq and I have been struggling with this query for a few days. From reading this forum, I have managed to get this far:
Dim noPic = (From f In myEntities.FriendLists
Where (f.UserID = Profile.ID)
Select f.FriendID).Except(From g In myEntities.GuestLists
Where g.EventID = _id
Select g.FriendID)
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I am trying to get everybody from the FriendList who is not already on the GuestList to display in a Repeater control. After reading the forum I was able to append .First() to noPic at the myNoPic declaration and finally get a result but that only gave me the first element. Does anybody have any advice on how to accomplish this?
Why doesn't CDate(integer) work where integer has format of YYYYMMDD ?and why won't this stupid site let me submit such a short question when I have nothing else to add except some waffle at the end
View 2 RepliesThis 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.
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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