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amaneet wrote: I am now trying to store the address of another variable in vb.net
In the world of Managed code, the address of a variable doesn't really exist the way it does in unmanaged C++. Any object or piece of code can be moved at any time, thereby invalidating any stored address you have on it. Addresses to code (function pointers) are handled by delegates in the .NET Framework. Variables are passed by reference, but that's not an address in the C++ sense of the word.
What are you trying to do with this?
Dave Kreskowiak
Microsoft MVP - Visual Basic
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Sir
i meant that can i implement the double link list in vb.net
Please provide help.
Thanks and Regards
Pankaj
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You can find a doubly-linked list implementation right here[^] on CP. It's written in C#, but is easily convertible to VB.NET if you want.
Dave Kreskowiak
Microsoft MVP - Visual Basic
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Sir/madam,
I am facing a problem in the interfaces.
I have a class named class1 which has the following implementation
class class1
implements inter
public sub abc()implements inter.a
messagebox.show("abc method")
end Sub
End class
Now i am creatin a interface
Public interface inter
sub a
end interface
Now i want the interface to implement in the window form named form1
public class form1
implements inter
private sub a()implements inter.a
end sub
now my question is ,
can i get the implementation of the function abc which is declared in class class1
without writing it here in the function a of class form1 again
If i have to redefine the implementation of the function abd of class class1
in the function a of form1 after implementing the interface in form1 class
then what's the use of the interface.
instead of the interface , i could not use the object of the class or making the function shared.
I mean what is the nead to to redine the same implementation again.
Interfaces compensates the multiple inheritance.
But the class where i am implementing the interface , i will write the code again there..
Finally what i want is , there is a funtion defined in the class .
i want to call that function in another class
without the use of object of the class or keyword shared.
i mean i don't want to write the same code again
can i make it possible using interfaces
end class
Thanks and regards
Pankaj Garg
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amaneet wrote: Interfaces compensates the multiple inheritance.
I don't think you have the right idea on what an interface is. It's not used to somehow allow multiple inheritance. I'll quote a book I have because it's better then what I can come up with.
"An interface defines only the signature of properties and methods, while a class can implement that interface by providing actual code for those properties and methods as necessary."
-Visual Basic 2005: The Language by Francesco Balena
All an interface is-is a definition of properties and methods to be included but does not supply the actual code. Each class must do that on it's own. So no, you can't write code in class1 and have the form class use it in the manner you have defined. Form1 class would have to write it's own code.
amaneet wrote: Finally what i want is , there is a funtion defined in the class .
i want to call that function in another class
without the use of object of the class or keyword shared.
You want to access a function but don't want to create an intance. Sounds like you want a shared function. So why do you say you don't want the shared keyword? If that's what you want I think your only option is a shared function.
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can u please brief how to use the interfaces
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The documentation on "Interface[^]" goes a long way...
Dave Kreskowiak
Microsoft MVP - Visual Basic
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hey friends....
actually m preparing a VB.net application on Visual Studio .net 2003
and i want the system compatibilities on differnt configurations and operating systems....
please go to the following link where i have made a sample desktop "New CGPA calculation software" and check out the compatibility of this application on your system
and please do let me know yr system configuration.
thanking you...
link is :
http://www.fileden.com/myfiles.php[^]
-- modified at 14:47 Saturday 3rd March, 2007
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The .NET Framework insulates most of the machine from your code. This really isn't necessary for a small app like yours. You're not doing anything that's really hardware dependant.
Dave Kreskowiak
Microsoft MVP - Visual Basic
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Hi guys
I have a problem when I use an Add-in to word, I want to get the filename / path of opened document.
(i.e i have a opened a document in word, now when i click my button it should return the filename / filepath of opened word document.
Thank you!
M. Nauman Yousuf
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Try to use
Application.ActiveDocument.Path & "\" & Application.ActiveDocument.Name
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Hello,
[VS 2005]
I am new to working with typed dataset and currently working on a project and have decided to use them.
I have about 20 tables in my database that are used my program.
I have created several designers and dragged some tables on them and created the relationship.
I have tried to do this in a modular way. i.e. one for updating, deleting, customers, another for updating, deleting stock. So i have tried to keep this clean and tidy.
And I have ran into a problem of having many designers that use the same tables. the customers table could be used in many designers that i have.
I think that this has made a whole mess, and not sure if i should have created 1 designer and put all the tables in there. Is it better to create 1 designer and put all the table in there?
My program is only small and have about 20 tables but could grow bigger in the future.
In big enterprise application where lots of table are used, what do developers do in this case?
Does anyone know of any good tutorials for the best practices for doing this sort of design.
Another quick question when you create a relationship between the tables. There are options to create constraints and foreign key constraints. What is the difference between these options?
Many thanks for any good advice on this.
Steve
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steve_rm wrote: In big enterprise application where lots of table are used, what do developers do in this case?
The database access code is usually written by hand, probably written with the help of something like Microsoft Data Access Application Block (see here[^]).
steve_rm wrote: I think that this has made a whole mess,
This is why we don't use the designers to generate all the code for us!
steve_rm wrote: Another quick question when you create a relationship between the tables. There are options to create constraints and foreign key constraints. What is the difference between these options?
You just about never need to do this unless you need the relationship inside your code. You can see an example here[^].
Dave Kreskowiak
Microsoft MVP - Visual Basic
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I have the timer counting 5secs til a form is closed, is there any way to link a progress bar to the timer (i.e. the progress bar shows the timer running down).
Cheers
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A Progressbar doesn't progress on it's own. Your code has to actively update the current value of the ProgressBar control to get the bar to move. This means that you can't just set a Timer for 5 seconds, sit back and do nothing until it fires. Your Timer has to advance the ProgressBar.
Setup a ProgressBar on your form. Set it's minimum value to 1, maximum to 10, and step value to 1. Set a Timer on your form for say 500 milliseconds (half a second). In the Tick event of your Timer, call the PerformStep method on the Progress bar. When the Value of the ProgressBar reaches 10, your done, close your form.
Docs on ProgressBar[^]
Dave Kreskowiak
Microsoft MVP - Visual Basic
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Nice one, sorted
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Below is what I have in the frmMain_KeyDown event
How do I call it from the Timer1_Tick event?
Dim strKeyPress As String = Nothing
strKeyPress = e.KeyCode.ToString()
Select Case strKeyPress
Case "Left"
R.X -= 10
Case "Right"
R.X += 10
End Select
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You should examine EventHandler and RiseEvent methods. You can rise the event inside the Timer1_Tick event. 
What a curious mind needs to discover knowledge is noting else than a pin-hole.
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You move this code to it's own method, then call it from the KeyDown event handler, passing the data the method needs to do its work. You do the same from your Tick event handler, but why are you calling keyboard handling code from a Timer?? And why are you converting the Keycode to a String when you don't have to??
Private Sub KeyHandler(ByVal keyCode As Keys)
Select Case keyCode
Case Keys.Left
R.X -= 10
Case Keys.Right
R.X += 10
End Select
End Sub
From your KeyDown event handler, you just do:
KeyHandler(e.KeyCode)
From your Tick event handler, you have to pass in whatever keycode you're going to use:
KeyHandler(Keys.Left)
Dave Kreskowiak
Microsoft MVP - Visual Basic
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Hi Dave,
I'm just messing with an image that is divided into 35 Squares one is picked at random then the Timer1 event fires and drops the square down the form, what I want to do is press the left or right arrow key and move the tile accordingly.
So I need to check throughout the timer event to see if the arrow keys have been pressed or not.
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Your tile coordinates would probably have class scope. This mean you can get to the coordinates from any method in your form.
Your Timer event should just be concerned with changing the coordinates, moving the tile down the form. It doesn't need to know anything about any keystrokes and doesn't need to generate any.
The second thing that the Timer event needs to do is redraw the form so the user sees the tile moving down the form.
Your keydown event should be doing just what it's doing - moving the tile coordinates left and right.
Dave Kreskowiak
Microsoft MVP - Visual Basic
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Cheers Dave
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Hi,
I am attempting to make and application that retrieves information about the active window in the system. I have always used the GetForegroundWindow function with no problems in both C++ and VB6.
However, when I attempt the call the function in VS2005, vb.net, I only return the window handle about a third of the time. The other two thirds it simply returns 0. The window type doesnt seem to matter since it has happened with many different windows.
This is my code for attempting to retrieve the hwnd...
Dim lhwnd As Long
Call ShowWindow(Me.Handle), SW_HIDE)
lhwnd = GetForegroundWindow
Me.Text = lhwnd
Call ShowWindow(Me.Handle, SW_SHOW)
I have tried it using command buttons, link labels and other control click events and it still doesnt seem to want to work.
I tried calling it as such also.
Dim lhwnd As Long
Call ShowWindow(Me.Handle), SW_HIDE)
Dim lhwnd as long = GetForegroundWindow
Me.Text = lhwnd
Call ShowWindow(Me.Handle, SW_SHOW)
and
Dim lhwnd As Int32
Call ShowWindow(Me.Handle), SW_HIDE)
lhwnd = GetForegroundWindow
Me.Text = lhwnd
Call ShowWindow(Me.Handle, SW_SHOW)
Although it doesnt show, i also even placed the application.doevent call inbetween each line but that did not help either...
any help can be appreciated...
Thank You,
Brent
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We need to see the Declaration of the GetForgroundWindow function. I get the feeling you just used the VB6 code without any conversion. The problem most people run into is that they don't know the difference between a VB6 Long type and a VB.NET Long.
In VB6, a Long is a standard 32-bit signed integer. In VB.NET, Long is a 64-bit signed integer. A VERY different number with different storage requirements.
For handles, you should be using the IntPtr type in VB.NET. So, for GetForegroundWindow, the Declare should be:
Private Declare Auto Function GetForegroundWindow Lib "user32" () As IntPtr
.
.
.
Dim foreWndHandle As IntPtr = GetForegroundWindow()
Dave Kreskowiak
Microsoft MVP - Visual Basic
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