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First off, this is an ASP.Net question, not one specific to C#. You should post it to the ASP.Net forum for more timely response.
Now, unless you personally make some attempt to persist your data source (or reconnect and query it each time) across page turns, it will not persist itself. At the very least, you need to bind your data source to its control after each page turn (Postback or not), and at most - meaning if you don't want to reload your data after each page turn - you need to persist it statefully. The static variable is a bit much for this application, but it proves the point.
Is ViewState enabled for your dropdownlist? If you're doing filtering after your initial binding it won't really matter since you'll need access to your datasource, not the expression of the data in the control, but it's something to check.
Other ways to do the same thing would be to push the data source to ViewState manually, or use the Session or Application objects - it all depends upon your needs.
I would recommend looking up the ASP.Net page life cycle to better understand what happens each time a page is turned (whether it's a new HTTP Request or a Postback).
Good luck
The most exciting phrase to hear in science, the one that heralds the most discoveries, is not 'Eureka!' ('I found it!') but 'That's funny...’
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Why doses C# not support Multiple Inheritances?
Is there any disadvantage?
Vikas Neema
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hi...
check this:
#
What is multiple inheritance? What are its advantages and disadvantages?
Multiple Inheritance is the process whereby a sub-class can be derived from more than one super class. The advantage of multiple inheritance is that it allows a class to inherit the functionality of more than one base class thus allowing for modeling of complex relationships. The disadvantage of multiple inheritance is that it can lead to a lot of confusion when two base classes implement a method with the same name.
source link : http://www.possibility.com/epowiki/Wiki.jsp?page=CppInterviewQuestions
you can implement multiple interface instead of multiple inheritance 
hope i helped
Tarek Elganainy
Computer and Systems Engineering Dept.,
Faculty of Engineering,
Alexandria University.
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See the last post here:
Why no multiple inheritance allowed in C#? [^]
It reads:
This is an answer on this question, as posted on a C# FAQ by Chris Brumme:
1. Different languages actually have different expectations for how MI works. For example, how conflicts are resolved and whether duplicate bases are merged or redundant. Before we can implement MI in the CLR, we have to do a survey of all the languages, figure out the common concepts, and decide how to express them in a language-neutral manner. We would also have to decide whether MI belongs in the CLS and what this would mean for languages that don't want this concept (presumably VB.NET, for example). Of course, that's the business we are in as a common language runtime, but we haven't got around to doing it for MI yet.
2. The number of places where MI is truly appropriate is actually quite small. In many cases, multiple interface inheritance can get the job done instead. In other cases, you may be able to use encapsulation and delegation. If we were to add a slightly different construct, like mixins, would that actually be more powerful?
3. Multiple implementation inheritance injects a lot of complexity into the implementation. This complexity impacts casting, layout, dispatch, field access, serialization, identity comparisons, verifiability, reflection, generics, and probably lots of other places.[/]
As far as I'm aware, the only language that supports full MI on .NET is Eiffel.
Full Eiffel on the .NET Framework[^]
Kevin
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i try to build a program in C# to lock a certain directory.
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Hesham yassin wrote: i try to build a program in C# to lock a certain directory.
Good luck then!
Smile: A curve that can set a lot of things straight!
(\ /)
(O.o)
(><)
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I am also saying Good luck..Tried sometime but not achieved
Regards,
Sylvester G
sylvester_g_m@yahoo.com
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ha:-Dha
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Hi ,
I want to access remote machines hardware , like CD-ROM Drive , WebCam etc.
But I am not sure where to look and frm where to start.
So can any one plz guide me to right direction ?
I am using sockets to access remote machine , so I am assuming streams are only way to get these hardware resourses , but how ?
Need help , thanks.
ZINK
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This can be done in a few ways, and this is one of them (not necessarily the best):
Use System.IO.DriveInfo.GetDrives() to retreive all drives, then use a formatter to serialize the DriveInfo objects to the NetworkStream.
As for webcam and other devices, you're gonna have to code API wrapper classes, mark them as Serializable, and again, use a formatter to serialize them to the NetworkStream.
Regards,
Shy.
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Hi ,
Shy Thanx for your reply.
Actually I dont want to get just the Devices name , but the actual device when u share your CD rom drive on netwrok , any one on netwrok can use ur drive and access th CD data in that CD rom drive.
So I want something like that .
Any sugestions ?
Thanks
ZINK
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AFAIK, sharing devices over the internet is impossible. Sharing them accross network computers IS.
However, I don't know how to make a device shared using code...
You would probably need to find the API function appropriate for the job.
Search CodeProject for articles, or google it...
Good luck,
Shy.
Added:
If, however, you want to enable browsing and controling of hardware devices over the internet, you would have to write a client-server application, in which the server sends information to the client regarding the devices, the client sends requests for information, and requests for execution of stuff (creating directories, deleting files, etc.), and so on...
You would have to design you're own protocol I guess.
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HI Shy ,
Thanks for your reply.
Yeh I have socket application runing on client and server. And I want that when client want to access data on cd on Server's CD Drive , server reads that data and send to client .
But not sure how to do this ???
Regards,
ZINK
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Well... That's a much bigger issue... These are stuff you need to figure out on your own. 
Search for articles and code exemples to get the idea...
Here are a few ideas and guidelines:
- You can use .NET Remoting to use objects from the server on you client.
This will release you from the need of designing an entire protocol.
You would simply instantiate an object and use it as if it was an object instantiated on the client's side.
So find material on .NET Remoting!
- If you intend to use serialization, here are a few ideas:
Lets say the client wants to receive a list of the directories in drive c:.
You can create a class which will hold the requested path, like so:
[Serializable]
class DirectoryListRequest
{
private string pathToExplore;
...
}Then you instantiate an object of type DirectoryListRequest and serialize it to your NetworkStream.
The server then deserializes it, reads the pathToExplore field and instantiates its own object of type DirectoryListReply.
Then the server serializes the DirectoryListReply object to the NetworkStream, and the client deserializes it, and so on...
Good luck,
Shy.
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matjame wrote: I want to knw if its possible to call a .css file on c#
No. CSS contains no functionaltiy for C# to call
matjame wrote: All I need is its layout to appear on my c# webpage.
Web pages are written in HTML, not C#. You can get aspx pages which are converted to HTML by the server, but CSS is not applied to the codebehind, it is applied to the HTML.
matjame wrote: Step by step on how to do this would be nice thank you very much
If you "View Source" on this web page you'll see how it is done.
<link rel="stylesheet" type="text/css" href="/styles/global.css" />
Upcoming events:
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* Reading: Developer Day 5
Never write for other people. Write for yourself, because you have a passion for it. -- Marc Clifton
My website
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I tried it but its givin me errors.
I will see if I cant fix it but Im battling.
And wer do I put it.
kagiso
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matjame wrote: And wer do I put it.
It goes near the top of the HTML or ASPX file. As I mentioned before: View the source of this page for an example.
Maybe it would be best if you bought a book on ASP.NET and learn the foundations of how it all works and hangs together.
Upcoming events:
* Glasgow: Mock Objects, SQL Server CLR Integration, Reporting Services, db4o, Dependency Injection with Spring ...
* Reading: Developer Day 5
Never write for other people. Write for yourself, because you have a passion for it. -- Marc Clifton
My website
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Hello everyone,
Well I’m working in a C#2.0 desktop application and I’m using numericupDown Objects to take numeric input. The only problem I’m having is that it can take more than one decimal points and I want to some how stop that thing from happening, like the control should not accept a decimal point when it already has one. So can u plz help me in this?
Thanks in advance,
Rocky
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You can try the following:
- Create a new component, which inherits System.Windows.Forms.NumericUpDown.
- In your new component override the OnTextBoxKeyDown() method, and inside it put code like this:
protected override void OnTextBoxKeyDown(object source, KeyEventArgs e)
{
if (e.KeyCode != Key.Decimal || !Text.Contains("."))
base.OnTextBoxKeyDown(sender, e);
}This should disable calls to base.OnTextBoxKeyDown() when the user presses the decimal key, and a decimal point is already present.
Regards,
Shy.
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hi,
the code provided by Shy will prevent the user from entering more than one decimal if and only if the user uses the key board to enter the data. what if one chooses to copy paste the data??
to handle this you need to override the event handler for ValueChanged and check for the decimal character.
regards
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thats a very good point u know... thanks
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1119 wrote: the code provided by Shy will prevent the user from entering more than one decimal if and only if the user uses the key board to enter the data. what if one chooses to copy paste the data??
You're right... I didn't think about it...
1119 wrote: to handle this you need to override the event handler for ValueChanged and check for the decimal character.
Wouldn't that cause flickering text?
That is, If a second decimal point is now present, and through ValueChanged you set the Text property to remove it.
The text would be drawn once before your code executes, and once after.
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shyagam wrote: Wouldn't that cause flickering text?
no, i don't think so. it will be fired only after the value is changed, just like the keypress event handler is fired for every key pressed. and if keypress event handler doesn't cause flickering, i don't see any reason why this should?
if you implement this, you don't need the keypress event handler and it will provide the same function.
there may be other ways to implement this as well.
regards
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That looks very helpful indeed thanks alot brother
Rocky
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