Check The Final Type Of A Variable?
Sep 6, 2010
I have a BaseClass, a DerivedClass1 and a DerivedClass2 from a third party library. DerivedClass1 and DerivedClass2 both inherit from BaseClass.There's a ContainerClass, from the same library, with a member variable ActiveItem, which can be of DerivedClass1 or DerivedClass2, so it is declared as BaseClass.I want to know if ActiveItem is of DerivedClass1, as it can change in runtime without notice.If I do
Dim isDerivedClass1 as boolean = TypeOf(oject.ActiveItem) Is DerivedClass1
then I get a compile time error, telling me that ActiveItem can never be of DerivedClass1 type.I have tried several combinations of GetType and TypeOf but it doesn't seem possible to check this. I have also tried to declare an auxiliary DerivedClass1 variable and comparing their types, but haven't got any luck either.
Edit:The following code doesn't compile in vs2005 SP1.
Public Class Base
Public x As Integer
End Class
Public Class Derived1
[code]....
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Jun 16, 2009
I want to see if a variable's type is string or double type. How to do it in vb.net immediate window?
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Apr 14, 2010
I have this function:
Public Sub DoStuff(ByVal type as System.Type, ByVal value as Object)
End Sub
The 'value' argument is always an array of the same type as 'type'. How can I loop through the values of the array?
I'd like to be able to do something like this:
DoStuff(GetType(Integer), New Integer(){1,2,3})
Public Sub DoStuff(ByVal type as System.Type, ByVal value as Object)
//Strongly types arr as Integer()
[Code].....
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Oct 10, 2009
I'm aware that questions like this have been asked before and I doubt it's possible, but I just wanted to make 100% sure that it isn't.In VB.net or C# (either language, it doesn't matter), I want to cast a variable to a type represented by another Type variable. Here's an example of the kind of code that would be needed in C#:
Object castMe = new Foo();
Type castTo = typeof(Foo);
Foo beenCast = (castTo.GetRepresentedType())castMe;
[code].....
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May 18, 2012
Public Class Form1
Dim x, c, number(0 To 19) As Integer
Dim s As Integer
[CODE]...
The variables in the brackets [example] do not actually have brackets in them in the original code. These are where the issues are. For both variables, it says, "The type for variable [variable] will not be inferred because it is bound to a field in an enclosing scope. Either change the name of [variable], or use the fully qualified name (for example, 'Me.[variable]' or 'MyBase.[variable]')." Now, I'm not entirely sure if this is a stupid question or not, as I'm used to VB '98 because that's what we use in my programming class at High School. let me know why this won't work.
-Note: The intention of this program is to continually loop the generation of numbers for this list until I tell it to stop. Button1 ends the program, Button2 generates the list one time only, Button3 is supposed to loop the generation of the list, and Button4 is supposed to end the loop, but not the program.
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Aug 24, 2009
I am looking for a good resource on variable naming conventions to illustrate variable type and where variables are declared. So I will have public variables, Private variables, private or local variables. I also may want to declare variables with the same name in different class code (i.e. in the code behind different forms). I am assuming good coding would dicatate a prefix for declaration location.
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Sep 17, 2011
I have the following code that I am using to parse out a test file. I am getting variable conversion error in Sub Main() when I assign file = Read(). The return value of Read() is a TextFieldParser type. How do I assign the proper variable type to "file" so I can write the output to a text file?
Function Read()
Using MyReader As New FileIO.TextFieldParser("C:UsersColinDesktopParse_Me.txt")
Dim currentRow As String
[Code].....
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Dec 22, 2009
E.g. how do I get VB.Net to statically type a local variable to be the static type of the expression on the right had side of the assignment?
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Oct 22, 2009
I want to use explicit conversion (CType function in VB.NET) to convert the variable d from double type to integer type and store the result as 132.
Imports System.Console
Module Module1
Sub Main()
[CODE]...
This is my code. But Visual Basic tells me an error: Error1Type 'i' is not defined.C:\Users\mihaispr\Desktop\Conversie explicita\Conversie explicita\Module1.vb1922Conversie explicita
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Aug 20, 2009
I have a number of controls (Device1, Device2, etc.) that all inherit from BaseDeviceControl. In the DragEnter event handler I am trying to test for the correct type by using the BaseDevvceControl like this....
[Code]....
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Feb 15, 2010
Writing an asp.net mvc app and i have something like this...
Public Class AA
'... has some variables...
End Class
Public Class BB
[code]....
So, now in my program, i just want to copy object of type AA to an empty variable of type BB?it makes sense to do this, as i expect all the fields in AA type object to be copied to the newly created BB type object, and the ExtraVariable in the BB type object i would (will) just assign a value to it later (after the copy) on my own time!!I know copying BB type to AA type would not be appropriate as there would be lost data!But im trying to copy AA to BB, I've used both DirectCast and CType to do this, and i keep getting "unable to cast" error!
Note: I'm using vb.net (but can read c#, no problems)
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Dec 2, 2009
What's the C# equivalent of
<% dim name %>
so you can use it for web forms in PayPal API integration?
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Jun 21, 2011
I recently downloaded VB 2010 Express so i am quite new to the language, but i have worked with dark basic, which seems to b very similar.Anyway, my problem is that i cannot seem to correctly set out my array of a custom type/class. i am trying to create two arrays, one of available entities and another of selected entities of which the user selects the entities to be dealt with in irrelevant ways. i have creates a button (called test) which adds some entities to the available list and all the entities come back the same value but they shouldnt be as you'll c in the code. i have run the step into command a found that "available.item(#).Name = " will change all of the entity's names.As of current i am working with lists as the array kept asking for a 'new' statement but i couldnt figure out where to put it.[code]
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Jan 8, 2009
[code]...
A first chance exception of type 'System.NullReferenceException' occurred in MyApp.exe
A first chance exception of type 'System.ComponentModel.Win32Exception' occurred in System.dll
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Jun 2, 2011
1- How can I check the size of a variable? Size in bytes, not length. (;
2- What data can be stored into byte variables? And what the maxium size of the variable?
3- How do I store data inside a byte variable?
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Mar 3, 2009
To check if a setting has been set, I currently use:
If My.Settings.Username <> "" Then If this the best way to check? Is there a better way?
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Jan 8, 2011
I have got a question to you. I want to know how I can check the listview items in form1.listview1.items and me.listview1.items to see that if both listview have got the same text property of the items then display the messagebox that says "you can't add the same items again. Please select a different item and try again!", otherwise display the messagebox that says "the items have been added".
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Nov 15, 2011
I am developing an application for multi user using vb.net with back end as ms-access. For the table name as employee_master, there is a column, name as student_profile having datatype as Yes/No .
[Code]...
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Aug 7, 2011
This line of code references a checkbox in a Gridview, how can I assign the value of the check box 1 or -1, I think it is for checked or unchecked, to a variable so that I can run an if statement against it, and change it to True or False?
dt.Rows(row.DataItemIndex)("DisplayString") = (CType((row.Cells(3).Controls(0)), CheckBox)).Checked
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May 15, 2011
I want to check If a variable is equal to some values or not, for example:
if a = 1 or a = 5 or a = 7 or a = 10
is it possible to do it like sql:
if a in (1,5,7,10)
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Jan 15, 2011
In Visual Studio 2010 is it possible to check the state of variables during run time. When a run time error occurs the error is highlighted and you are able to mouse over different variables to see their values when the error happened. I would like to do something similar except without the error.
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Nov 8, 2011
I have a struct setup like the following[code]...
I then loop through a counter and add each PersonInfo object to the Dictionary. The Primary defaults to false if the Code is already in the Dictionary, but if it has not been inserted into the Dictionary, I want to set the Primary to True. It would be easy to check if the Code was the key, but I can't because the Code is not unique.
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Nov 18, 2011
I have some web pages that include other pages, and I need to check if a variable (a string) has been declared in the page or not.
I was exploring try catch and finally, but im always getting a compiler error saying the variable doesnt exits.[code]...
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Jul 16, 2009
I'd like to know if my textBox1 variable has the ABCAttribute. How can I check this?
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Jun 22, 2009
i have a property (items) that i want to use for either a checkedlistbox or a standard listbox depending on the value of another property.
heres the code i wrote that doesn't work:
[Code]...
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Mar 6, 2010
In some part of my code i need to redefine the type of variable that was defined with a different type at the beginning
dim T as new MyClass
...
redefine T as ( MyClass2)
i do not want to do something like
dim T
t= new MyClass
.....
t= new MyClass 2
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Sep 17, 2009
I have some code like:
Lookup(Of String)("Testing")
Lookup(Of Integer)("Testing")
And both of those Lookups work great. What I'm trying to is call the appropriate LookUp based on the type of another variable. Something that would look like...
Lookup(Of GetType(MyStringVariable))("Testing")
I've tried to Google this but I'm having a hard time coming up with an appropriate search.
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Mar 17, 2009
What's the main problem if I don't declare the type of a variable? Like, Dim var1 versus Dim var1 as Integer.
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Apr 10, 2011
Dim myObject As Something There I defined my variable myObject of type Something. But, as you can see, I am giving it no value yet. Sometime on runtime I want to check if myObject is holding a value or not. I tried this: If myObject <> Nothing Then But apparently I can't do such comparison.
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Nov 22, 2006
I want to Assign the Value to Multiple Variable of same type in .net and that to in one line of Code.
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