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?
I'm trying to declare an enumeration and one of the names I'd like to use for an item is not usable apparently. Where I am declaring 'STEP = 3', I get this error message in visual studio: "Statement cannot appear within an Enum body. End of statement expected." Is it possible to use STEP as an item name somehow? [Code]
Which is better, using a nullable enum or adding the value None=0 to your enum list?Using nullables requires more code, but I kind of like it since it forces me to think about the possibility. Otherwise I'm liable to forget about the None enum and fail to account for it being a special case.
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?
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.
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.
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]
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:
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)
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??
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)
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?
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] .....
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
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?
Recently I found a way to make CType work with generics (FYI, VB 2010 Express with option strict on). Say I have two generic types, T1 and T2, with variables x as T1 and y as T2. y=CType(x,T2) diagnoses with "Value of type 'T1' cannot be converted to 'T2'". y=CType(CObj(x),T2) compiles cleanly, and it works fine provided that T1 can be converted to T2. Failing that, an exception will be raised at run-time. Obviously, a downside of this is the boxing performance hit. Also, it is a half a step backward along the road to strong typing (a type conversion problem is discovered at run-time vice compile-time).
These objections aside, consider the GSU class below. There are two ways to do a generic CType of a variable, and then there is a way to do a CType of an entire array. GSU is sufficient (see sub Test) to convert an item or an array of items between, for example, all the numeric types (byte, short, double, ...). Exception handling remains to be done.
Type conversion code tends to get lengthy, so I think this is a nice result. What do you think? I am guessing that CType has some pre-generic smarts in it, and all I did was find a way to exploit it in the context of generics and option strict. I am mostly interested in generic tricks for value types.
Ever since I moved from VB6 to VB.NET somewhere in 2005, I've been using CType to do casting from one data type to another. I do this because it is simply faster to type, used to exist in VB6 and I do not know why I have to be using DirectCast if there is apparently no difference between them.I use TryCast once in a while because I understand that sometimes casting can fail. I however cannot get the difference between CType and DirectCast.
Public Class MyDbTransaction Implements IDbTransaction Private itsTransaction As IDbTransaction Public Sub New(ByVal trans As IDbTransaction) If trans Is Nothing Then Throw New ArgumentNullException("trans")
1. I have three classes. Now I want to know how do I convert object to my class runtime?
for example, Dim obj as New Object obj = CType( MyPassedObject, Class1 )
Now, in above code, MyPassedObject can be Class1 or Class2 or Class3 but it is passed as Object. So is there any way that I can convert into CType as per the type of that object, directly to that class? I mean, I can pass object name into parameter and write down CASE statement here to convert to that class but I do not want to write down Case statement for each of my class, so just want to know is it possible anyway?
I mean just for example, Can I do something like obj = CType( MyPassedObject, GetObject('Class1') or any other way?
2. Now for this obj, I am getting properties runtime and setting values and then updating.
for example,
Dim PropertyInfo As Reflection.PropertyInfo() = obj.GetType.GetProperties()
Now, Will it work fine if obj has been declared as Object and then I typeCast it runtime and then I get properties and set its values. Will it work if obj's variable type is Object or it must be that class type itself.