IDE :: CType Overflow When Converting Minimum Long Value
Oct 1, 2010
I'm developing a custom control for numeric input that does some basic value range checking and have run into an issue when I set my property ValueMin equal to Long.MinValue. The IDE generates the following line in form1.designer.vb file that subsequently is flagged as generating an overflow.
Me.NumericInputBox1.ValueMin = CType(-9223372036854775808,Long)
I've done some checking using the Immediate Window with the following results.
?Long.MinValue
-9223372036854775808
?ctype(Long.MinValue, Long)
[Code].....
It appears that the CType function does not recognize the minimum Long value when the value is typed into the function, but works fine if it is passed Long.MinValue or a string with the value. It works fine for a typed in value equal to (Long.MinValue + 1). This problem only occurs with the Long (Int64) type.
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Dec 6, 2010
I am creating a 'generic input dialog': InputDialog(Of T).The idea is that I can create new instances of this dialog for different values of T. For example,I can create an InputDialog(Of String) and it displays a textbox.I create an InputDialog(Of Boolean) and it displays two radiobuttons (I could use a Checkbox, irrelevant).I create an InputDialog(Of Date) and it shows a DateTimePicker.
I do this by simply checking the type of T at run-time.In this way it is not really generic, as the dialog still has to know which type T is (which is usually not the case), but the generic is in the fact that the T can be multiple types that require a TextBox. For example, InputDialog(Of String), (Of Integer), (Of Single), (Of Double), etc, all simply display a TextBox (and it is validated later),so I still want to use generics as much as possible.Anyway, the result of the dialog is of course a property of type T. This property needs to return the value in the textbox, converted from string to T, OR the value in the DateTimePicker, converted from Date to T,OR the checked property of the 'Yes' radiobutton, converted from Boolean to T.In order to convert from any object to T I googled and found this
vb.net
Imports System.ComponentModel Public Class GenericTypeConverter Public Shared Function FromObject(Of T)(ByVal value As Object) As T Dim tc As TypeConverter = TypeDescriptor.GetConverter(GetType(T)) Return CType(tc.ConvertFrom(value), T) End Function End Class
I have to use this, I cannot simply CType a string to T since a String cannot be converted to any type T.So, my Result property looks like this at the moment:
vb.net
Public ReadOnly Property Result()[code].....
This actually works for Strings, Integers, Doubles, Singles, etc. I pass it the String in the textbox and it converts it to 'T'(note: T is then a String, Integer or Double!) just fine.So, it can convert a String to a String, Integer or Double without any problems (I am validating the text before using the Result property so it will always be a valid integer, double, etc).However, it does not work for a Boolean, nor for a DateTime. When I try that, it says "BooleanConverter cannot convert from System.Boolean" or "DateTimeConverter cannot convert from DateTime". I realize it is a bit of a strange thing, since the object already IS a Boolean or a Date(Time) so no conversion should be done at all, but this doesn't work in design-time because I need to return the objects as type T.I know that T will be Boolean when the value to be converted is a Boolean, and that T will be DateTime when the value to be converted is a DateTime, but the designer does not accept a simple CType. As I said, it does not accept this:
Return CType(rbYes.Checked, T)
because 'Boolean cannot be converted to T'.
However, I did find a way to make it work, but it seems like a complete hack... I can assign the boolean to an Object and then convert that using CType:
Dim obj As Object
obj = rbYes.Checked
Return CType(obj, T)
This works, it's accepted during design-time, and it works during run-time, but it seems very wrong... Is there no better way to handle this?
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Nov 23, 2010
Here is the error that is getting thrown:
System.Data.SqlServerCe.SqlCeException was unhandled
HResult=-2147467259
Message="An overflow occurred while converting to datetime."
NativeError=25933
Source="SQL Server Compact ADO.NET Data Provider"
StackTrace:
[Code]...
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Aug 26, 2011
I have a DateTime Picker that I have set Format to "Custom" and CustomFormat to "dd/MM/yyyy HH:mm"
When the user changes the date time it all works fine and update the table no problem.
If the user does not change the date time I get the error[code]...
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Feb 22, 2012
Edit So the solution I posted from Jenner at VBforums was, obviously, in VB, and I used an online converter to port it to C#. Something was lost in translations, and that's why it was 10 miles off. I'm guessing I am just misunderstanding what the algorithms at the Proj.Net discussion boards are for and that's why they weren't doing what I wanted them to.
[Code]...
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Apr 1, 2010
Does anyone has the formula to convert X,Y,Z,Vx,Vy(cartesian 5D) as well as Azimuth, Elevation(Angular 2D) to Lat Long Alt?
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Nov 22, 2011
I'm trying to compute the password expiry date, and most of the example code is in C# One sample has:
[Code]....
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Jun 26, 2009
I'm pulling records from a db table (sybase) where I have run into a problem with a long varchar field. Using the OLEdb class I convert the field into a string variable which works fine in most cases, but there are problem with a few records. Examining the field in the database it shows that the value is not null, but the length of the field is 0.(SELECT field, length(field) FROM table). When I try to convert this into a string the result is rubbish.strContent = objReader.Item(i). I can't figure out what's the problem here, so I have avoided the issue by doing a table update before I start the process of getting data (I set the field value to null if field.length = 0
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May 4, 2012
I'm using Visual Studio and table adapters using an Access DB as the backend. I need the minimum 4 digit value. I want to get next available 4 or 5 digit number. And this will change depending upon the users request. Currently I use a table adabpter query. But how would I write a query. I suppose I could do a long iterative loop through all values until I see a 4 digit.But I'm trying to think of something more efficient.
Function GetNextAvailableNumber(NumofDigits) as Long
'SQL Code Here ----
'Query Number Table
[code]....
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Sep 18, 2011
Is there a easer way of coding in stead of wrighting long long paragraphs like this in one line [code]All of this is on one line and i got lots of info to put down.."The game will begin on your 16th birthday with your mother waking you up. Today you are to go to the castle for the first time. Leave your bed and open your dresser for a Strength Seed. "
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Dec 26, 2009
In Visual Studio 2008 I am using :Private Declare Function BlockInput Lib "user32" (ByVal fBlock As Long) As Long To stop input from occuring during a search-replace operation.
BlockInput(True) ' do not allow input during search and destroy
Dim cursorIcon As Cursor
cursorIcon = Cursor
Cursor.Current = Cursors.WaitCursor
Then setting it to false at the end of the operation. It did not work, so I thought maybe it was because I was calling it from a child window, so I created a function in the mainwindow, and ran it like this:
FrmMain.BlockFrmMainInput()With these functions is the Main window:
[Code]...
It did not solve the problem. I thought maybe it was because I was running under the debugger, so I tried compiling and running it debugger-free, but that did not do any better. I am still getting input when I double-click the mouse on either form.
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Jul 7, 2010
have a look at this code Dim colors() As KnownColor = CType(System.Enum.GetValues(GetType(KnownColor)), KnownColor()) Since CType is a function that returns DataType ,But here as in the code it seems that CType() is returning array having values that is assigned to color() array. How this is happening?
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Jul 24, 2009
I have a number of different object types that I would like to pass into a function. All my objects are created from classes with a .Description property. Is it possible to determine the type of object for use as the 2nd parameter in a CType call at runtime? e.g. Debug.Print CType(MyObject, TypeOf(MyObject)).Description (I have Option Strict On) I get errors when I do this.
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Mar 24, 2011
In vb.net, I got an Enum defined As Integer:
Enum enUtilityTypeDetailStudentEntryWorkflow As Integer
enUTDSEW_Default = 379
[code].....
This works but it adds a lot of noise to the code and it seems like the Enum is already defined as an Integer, making me think, why do I have to assign it again?
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Sep 26, 2011
I cant understand why this does not work! Hope for your intelligent answers ;)
With
CType(Controls(PicsGame(GameCount)),
PictureBox)
BorderStyle =
BorderStyle.None
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Feb 29, 2008
Is it possible to change a datarowview object to an integer?
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Nov 1, 2009
dim testpanel as new panel
dim test as CType(testpanel, Control))
msgbox(typename(test)) ' it gives me "panel"
'i dun get it, how can typename of test give me Panel when i explicitly call it to be converted to a Control type?
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Jun 16, 2010
I am an experienced C/C++/C# programmer who has just gotten into VB.NET. I generally use CType (and CInt, CBool, CStr) for casts because it is less characters and was the first way of casting which I was exposed to, but I am aware of DirectCast and TryCast as well. Simply, are there any differences (effect of cast, performance, etc.) between DirectCast and CType? I understand the idea of TryCast.
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Dec 13, 2009
I turned option strict on, wich gave me some errors. The errors are quite easy to fix, but it seems like there are several ways of doing things. [code] 'previoustime' is declared as a TimeSpan, and the column "sluttid" is defined as a TimeSpan-column.Now, as far as I know, there are two ways of solving this; using CType and using DirectCast, like this: [code]
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Jul 16, 2010
Assume that I have this declaration (according to MSDN):
Private Declare Function PostMessage Lib "user32" ( _
ByVal hWnd As IntPtr, _
ByVal wMsg As UInteger, _
[code]....
And this is how I use it:
PostMessage(hWnd, 516, CType(2, UIntPtr), CType(0, UIntPtr))
Option Strict is turned On. So the questions are:
1. Do I need to use UIntPtr in declaration or it will be better to use UInteger?
2. Do I need to use CType function in these cases or there is a better way for this or I need to avoid declaring pointers?
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Oct 25, 2011
does your IDE ever get amnesia?in the line before it is clearly defined.in the following line it is not.Maybe it's a faulty translation from Tangible Software.the C example i'm looking at:
IAnimatedMeshSceneNode* newNode = (IAnimatedMeshSceneNode*) oldNode->clone();
translated as:
Dim newNode As IAnimatedMeshSceneNode = CType(oldNode.clone(), IAnimatedMeshSceneNode)
had to make a dummy for it because i can't use arrays with CType.
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Jul 12, 2010
The below is a snippet from VB that I am porting to a C# rewrite. My question is what is receipt_date after the assignment? Is it still an object or is it a string?
Dim receipt_date As Object
receipt_date = CType(dr.Item("RECTDT"), String)
Would this be the correct C# counterpart?
object receipt_date;
receipt_date = dr["RECTDT"].ToString();
After both of these execute would the VB version, receipt_date be equal to the C# version?
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Feb 25, 2011
[Code]...
What happens when a user wants to alocate "" as Item(DurationColumn) to integer? I get an exception. clean solution to avoid this and set 0 for ""?
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Jan 30, 2012
I have this class: Public Class Foo
[Code]...
In the f = "Bar" assignment I loose the previous X and Y values previously assigned. There's a way to overload the operator to assign to the "Value" member instead of creating a new Foo class? Or a way to obtain the target of the assignment to copy the values??
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Jan 26, 2011
I am receiving the following error:
Object reference not set to an instance of an object. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.
Source Error:
Line 21: 'Determine the maximum pictureID for this user
Line 22: Dim results As DataView = CType(maxPictureIDDataSource.Select(DataSourceSelectArguments.Empty), DataView)
Line 23: Dim pictureIDJustAdded As Integer = CType(results(0)(0), Integer)
[Code]....
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Oct 31, 2009
i've got a problem here whereby my ctype doesn't work.firstly, to replicate my case briefly, i've created an extension of control class
[code]...
father.getheight 'compiler writes: Panel class doesn't support getheight, but I've already converted it to a Control with CType!end sub of course if i dim father as Control it works perfectly, but in my case father may be other objects as well that aren't controls so I had to dim father as a general object, is there a fix so i could properly convert father into a Control object?
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Sep 24, 2010
I have a class that overrides Ctype operator to have conversion from and to String :
Public Class TotoToString
Property value As String
Public Sub New(ByVal V As String)
Me.value = V
End Sub
[Code] .....
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Dec 27, 2009
I need to programmaticlly check one RadioButton1 in GroupBox1 in my Form.The name of RadioButton and his parent GroupBox is received from global variable 'names'.How to change GrpBx1 to names(0)?
VB.Net
Dim names as String() 'GrpBx1,RadioButton1
'WORKING but not exactly what I wanna while it's fixed to only one GroupBox:
CType(Me.GrpBx1.Controls(names(1)), RadioButton).Checked = True
[code]....
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Oct 13, 2009
Public Enum Fruit
Red_Apple = 1
Oranges
Ripe_Banana
End Enum
Private Sub InitCombosRegular()
[Code]...
Why does the Ctype work and the Directcast does not with the same syntax? Yet if I cast the selectedValue to an int before I DirectCast, then it works
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Oct 12, 2009
Does DirectCast, ctype, etc., are common function? Why it return type, and how do I used it? Is there others function where I need learn to be dot net expert?
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