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'm trying to write a (WPF) program with Option Strict on, but I have a problem.
I have a Canvas with a background image, and I want to use the coordinates of where the canvas was clicked to determine what should happen next. (Something like this)
Dim p As Point = e.GetPosition(DirectCast(sender, Canvas))
Dim imgColorMap As System.Drawing.Bitmap = My.Resources.ColorMap
Dim c As System.Drawing.Color = imgColorMap.GetPixel(p.X, p.Y)
This gives me the error: "Option Strict disallows implicit conversion of 'Double' to 'Integer'" for p.X and p.Y I have tried several things, like Math.Round but strangely enough that also returns a double.
How do I cast/round these Double values to Integer, so I can use them in my GetPixel method?
I am working with some VB.Net code that seems to be casting a boolean value to an integer using CInt(myBoolean). The odd thing that is happening is that it returns -1 if the value is true. For example:
CInt(True) // returns -1
CInt(False) // returns 0
Is this common in other languages? I thought that a boolean would be 1 if true and 0 if false. Also, is there a way to make VB assign 1 to true instead of assigning -1?
Is there a fast way in VB.NET to take a 32-bit int and cast to a 32-bit float while preserving the underlying bit structure? BitConverter will do this, but I'd like to cast it directly without involving byte arrays.
View 1 RepliesI 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]...
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'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 am passing Date Field to SQL Database. Field is declared as String in the VB.Net Application. I wrote a piece of code for casting to Date
[Code]...
I am running into a simple issue for which I cannot find an effective solution.
I need to convert 2 D array of objects to 1D String.
Dim saRet(,) As Object = Nothing Dim fileLineArray() As String = Nothing
SaRet = xlrange.Value //it gets values assigned as objects
In a loop....
fileLineArray(i) = Cstr(SaRet(i,0))
I get the error, index was out of bound. ToString isnt able to convert 2d array of objects to 1 D.
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
[Code]...
[cod]e...
will convert a string containing a decimal value to a nicely formatted currency value. Is there anyway to do this without first converting the string value to a decimal?
I'm trying to set an Integer value from my.settings.The values comes frpm a listbox, and then inserted to settings (set to specialized.StringCollection)The problem is when i'm trying to get the values and apply them to my function.Error code: Conversion from string "65 & 71" to type 'Integer' is not valid.To me it looks right, but maybe i'm missing something.
Code: Dim test2 As Integer Dim test As System.Windows.Forms.Keysm trigglist As New StringBuilderor Each item As String In
[code].....
how to implement Nullable Parameter of type string in vb.net
Function:
sub savedetail(byval name as string, byval age as integer)
if name isnot nothing then
some work
end if
[code]....
I have 3 similar functions, that only change based on numeric type:
<Extension()> _
Public Function ToNullableShort(ByVal str As String) As Short?
Dim intReturn As Short
[Code].....
I was trying to make a generic function out of this, but couldn't do it. How can I make a generic function that will take a specific T and make it a Nullable(of T)?
So I'm building an application that is going to do a ton of code generation with both C# and VB output (depending on project settings). I've got a CodeTemplateEngine, with two derived classes VBTemplateEngine and CSharpTemplateEngine. This question regards creating the property signatures based on columns in a database table. Using the IDataReader's GetSchemaTable method I gather the CLR type of the column, such as "System.Int32", and whether it IsNullable. However, I'd like to keep the code simple, and instead of having a property that looks like:
[Code]...
how can i convert these datatypes: date to string and integer to string.Because it must be in a string datatype when I display it in a datetimepicker and textbox.
View 3 RepliesWhy is it that when I convert a string with value "22.882" to double, using Dbl() it loses precision and is converted to 2288.2?
I have to use a double since I'm using the constructor of System.Web.UI.WebControls.Unit[URL]..
I am currently working on a custom data type, and wanted to implement a = operator.
I data type is a nullable date that returns a string value if date was supplied.
I want to allow the variable to be set like this
Dim nd as New NullableDate nd = Today Does anyone know how this can be done, or can anyone point me in the right direction?
How do I convert from a string to an integer? Here's what I tried:
Price = CInt(Int(txtPrice.Text))
I took out the Int and I still got an exception.
I know this is a proper enum:
Private Enum Months
JANUARY = 1
FEBRUARY = 2
...
End Enum
However, I want to have an enum where the string will solely be integers.
Example:
Private Enum ColumnCounts
01 = 5
02 = 4
03 = 40[code].....
Essentially, I didn't want to put the f in there, just wanted to do 01. The way this will be called is:
Select Case (nRecordType)
Case "01"
...
Case "02"[code].....
Because I'm not making an instance of it and not calling a constructor, there's no way to autopopulate a Dictionary.And I don't want to convert to integer so I'm not going to do an array. That is just in case eventually the value gets above 99 and the next value would be A0.I'm trying to think of easy future changes to this and backwards compatability.If you need more explanations, let me know.
Edit 2:This is what I've done now and I think it should work:
Public Class Part
Private Shared columnCounts As Dictionary(Of String, Integer) = New Dictionary(Of String, Integer)
Public Shared Function ValidateColumns(ByRef lstFiels As List(Of String)) As Boolean[code]....
I can't verify that it's going to do what I want to, but it doesn't give me an error when I build it so I'm crossing my fingers.
[code]This code wont work, it claims it cant be converted from a string to integer, i have tried CInt, but that doesnt work either.
View 32 RepliesI get an InvalidCastException was unhandled on converting the .value to .text but I can't figure out how to convert it. Tried a few different ways but nothing seems to work. load a file from disk and have that be assigned to the trackbar.value?
Dim FileName = (App_Path() & "SettingsPingTimeout.txt")
If File.Exists(FileName) Then
lblPingTimeout.Text = "Ping Timeout: " &
[Code]....
I would like to convert for example the string "98" to the integer 98. Also, is there a way to specify that the value contained in the string is in hexadecimal and that "98" gets converted to 152?
View 5 RepliesHow would I ask the user to input what type of engine they want and getting an output of $150
Console.WriteLine("Enter EngineChoice for your vehicle:")
Response = Console.ReadLine()
EngineChoice = Convert.ToString(Response)
[code].....
If strCardNum.Length <> 5 Then
MessageBox.Show("Please enter a 5 numbers.", _
"Georgetown Credit", _
[code]....
[URL].. and why it wont let me convert string to integer? i was following tutorial learning VB 2008 using 3.5 framework
View 8 Replies