I have tried to write:
Event EventName(Of T)()
But Visual Studio tells me that "Type parameters cannot be specified on this declaration."
Is such a declaration possible or will I have to put T as a regular argument?
I have two class like this[code]...
The red code does not works. How do I get the type of data to declare, for example, a Specific Instance(Of integer) if Data is integer, and also Specific (of SomeClass) if Data is SomeClass?
I'm wondering whether it is possible to declare a global variable in a click event. I need to declare an array of a specific size. The specific size is generated using a series of IF statements. I only need to know how to declare it.
View 1 Repliesi want to know how to use vbscript to declare the function that handles the button onclick event or set a function that handles all button onlick event! both will do i.e） ihave a function
"sub xxx()
end sub"
and i generate the buttons using vbscript. i can declare the button id, text without problem.
--dim obj as new button()
obj.id="aaa"
obj.text="ooo"
the above lines work just fine but when i write obj.onclick = "xxx", it doesn't work. by making settings on the function to handle all button onlick event is also acceptible for me!
Is it possible to have a sub that is triggered when any control of a specified type is clicked (or some other interaction), and then within the code of that sub, determine the sender and depending on the sender perform an action?For example, you create buttons dynamically, and assign them a name based on a counter that tells the number of buttons on the form. Now you click on a button, but there was no code written for 'button123.mouseclick' specifically. Instead, you get the name of the sender (button123) and you do something specific to that button.[code]
View 5 RepliesI am teaching myself VB, and when I try to run this program, I am getting "An error occurred creating the form. See Exception.InnerException for details. The error is: Object reference not set to an instance of an object." If I was to declare the variables inside each event handler, the program runs, but why won't it run when I make the scope public? Seems repititous having to declare the variables in every event handler. [code]
View 7 RepliesTo the point: I need to transfer a custom object's event through a generic collection object containing these items so that any class using the collection can see that changes were made to one of the items in the collection.
I.E. An item event that triggers a collection event
[Code].....
Due to the application requirements, I need the Collection and Items to send immediate notice of various changes that occur to the Collection Class and its items. I've already got my events set-up regarding for the Collection Class, but I'm struggling with coming up with a workable solution for raising events for the items.
I've got an event for the DeviceLayer item set-up, but how do you transfer that event through the CollectionClass so that any other class using it will see that there was a change to one of the items in the collection?
We have migrated our Vb6 application to VB.NET using a third party tool. Now we are in a process of Refactoring and introducing object oriented concepts in the application.
In VB6, we were using structures in many places. As a part of introducing object oriented programming,
1. is it a good idea of changing all Structures to Classes? or Is there a concept of "Generic Structure" similar to Generic collections, Generic classes?
2. Can some one guide me any source containing guide lines or best practices for applications that are migrated to VB.NET from VB6 and implementing object oriented programmaing.
Consider:
Public MustInherit Class Column
Public ReadOnly Property ReturnSomethingUseful() As Object
Get
'return something useful
[code]....
But this gives the following error:
Public Overrides Function ParseValue(sValue As String) As Boolean'
cannot override 'Public Overridable Function ParseValue(sValue As String) As Object'
because they differ by their return types.
I accept that you can't do this, but I'd like to be able to preserve the semantics of what I'm. trying to do, which is to have an untyped version that deals with Object, but a typed version in derived classes that knows about the specific type T.
I have a Journal that records entries for different types: Journal(Of ParentT)
[Code]....
I am trying to construct a generic interface class with generic functions. My goal was to use this to implement multiple worker classes for database interaction that have the same basic functionality. Each class will deal with different object for example, category, product or supplier but unless the the functions in the interface are generic that this won't work.This is the interface code that I have but I don't know if I have done it correctly. [code]
View 2 RepliesI am trying to create a list of a generic type in vb.net 2.0 framework.
This is the generic type definition:
Public Class GenericParamMap(Of T)
Public Sub New(ByVal pParamName As String, ByVal pPropValue As T)
mParamName = pParamName
[Code]....
The compiler does not allow a "T" in the method's parameter because it's not defined, but I'm not sure how or where to define it. I thought it was okay to have a generic method definition.
I am trying to write a generic method, to avoid code duplication, which will create or activate a Form as an MDI children, based on its type. But I have to lines in error (see comments).
[Code]...
If i have an object that implements an interface (and don't know the exact object) i can call a sub (DoSomething) by going:
vb
Dim iObj = trycast(something, iInterface)
if iObj isnot nothing then
iObj.DoSomething()
end if
How can I do this for a Generic? such as...
vb
Public Class TestClass(of T)
Public sub DoSomething()
....
end class
I have been using a pretty slick generic invoke method for UI updating from background threads. I forget where I copied it from (converted it to VB.NET from C#), but here it is: Public Sub InvokeControl(Of T As Control)(ByVal Control As t, ByVal Action As Action(Of t))
[Code]....
I can do this without problem.
Class A
End Class
Class B : Inherit A
End Class
Dim Obj1 As A = New B
I've read thru Iceplug's tutorial on control arrays and got it working. I tried to add a new event by basically copying his click event code and calling it a doubleclick event. I used the proper addhandler and assigned the correct name to my sub. I have the click event changing the background color to blue and the doubleclick event changing the background color to green. The background color does not change to green. Why?
Heres the tutorial with my new code encased in asterisks ...
Code:
Imports System
Imports System.Windows.Forms
Public Class form1
[CODE]...
I am using VB.NET for Windows applications. What is the difference between Load event,Activate event and Enter event in the Form and in which order the above event is executed.
View 2 RepliesI'm trying to validate a few things in a form I'm building. It has a datagrid with clients info (taken from an access database) and a few textboxes where the user can type some search criteria. The thing is that those same textboxes are used to add new clients to the database and to modify a client's information if one from the datagrid is selected, so I made it that the buttons to insert and modify clients are disabled on load and thenevery time the text on a textbox changes ("TextChanged" event) they become enabled. So far so good. But then I wanted to make it so when a client from the datagrid is selected both buttons become disabled again until the text on a textbox changes (to make sure they're adding a different client and not the same one that was
selected).
I tried using the CellClick event from the datagrid to disable the buttons, but since every time a client is selected from the datagrid the info is shown on the textboxes, this triggers the TextChanged event too, and the buttons become available.So, is there a way I can tell the TextChanged event not to be triggered when the CellClick event occurs?
I have a label called "test" in my Index.asp page in my MVC view folder. I want to be able to change the value of it in my controller class.
View 1 RepliesI have this H file in C, which includes[CODE]...
I get an error :FatalExecutionEngineError was detectedMessage: The runtime has encountered a fatal error. The address of the error was at 0x79e71bd7, on thread 0x11f0. The error code is 0xc0000005. This error may be a bug in the CLR or in the unsafe or non-verifiable portions of user code. Common sources of this bug include user marshaling errors for COM-interop or PInvoke, which may corrupt the stack.How do I translate it correctly ?
In C# we do
byte[] imageData = new byte[];
SqlCom.Parameters.Add(new SqlParameter("@ImageData", (object)imageData));
which makes the imageData variable as an object.But How do i do this in Visual Basic??
Dim imageData As byte() = new Byte()
SqlCom.Parameters.Add(new SqlParameter("@ImageData", ?? ) <-----What Should i do here?
My code is like this
conn.Open()
Dim cmd As SqlCommand = New SqlCommand("SELECT PhotoID From Photo " & str8 & " And Photo = @Photo", conn)
cmd.Parameters.AddWithValue("@Photo", CType(Photo, Object))[code]....
It comes out error like this:The data types image and varbinary are incompatible in the equal to operator. What should I do?
To declare an object in JS i can simply do the following:
var house = new Object();
house.window="square"
house.color="green"
In asp.net (VB) if i try doing the same
Dim house = new Object()
house.window="square"
i get an error: System.MissingMemberException: Public member 'window' on type 'Object' not found.
Do i have to create a house class before i can reference house.window? Is there no way to do it without creating a class?
In my VB 6.0 code, I declare have the following line[code]...
However, in VB.NET, I get the error "expecting declaration". Isn't this a declaration statement? Is there a good reference for finding the differences between VB.NET and VB 6.0?
In c++ we declare integer's hex value like this
int myint=0xabcd;
so how to i declare integer's hex value in vb.net
I want to know if it is possible to declare a variable thrice.
[code]...
i am making a program and the program runs too slow, so i would like to declare my functions at once.. not like this :
[Code]...
How to declare a datasource?
View 1 Replieshow to declare a textbox because my computer for a particular textbox say that "is not declared"
View 9 Repliesi know it's probly really easy. but how do i declare App.EXEName
View 10 Replies