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hey...could anyone tell me what are interface and how do u use them...eg Idisposable, Iserializable. Simplicity would be greatly appreciated.
Thanks
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Interfaces are contracts that ensures your implementation (either a struct - though not a good idea, unless required because of boxing when casting to that interface - or a class or another interface) implements a certain method, property, or event. Read 13. Interfaces[^] in the C# Language Specification for more details, including the difference between implicit and explicit interface implementations.
As far as how to implement certain interfaces - or rather what they do - you really need to read in the .NET Framework SDK[^] what they do. Many of the topics in the SDK documentation give examples, and there's always more abstract documentation (about how to use Framework features, like serialization and the disposable pattern) if you read Programming with the .NET Framework[^].
Reading is important. Just guessing what they do would teach you the intricacies of how those interfaces work with other classes (like how IFormatter implementations use the ISerializable interface, and that Types must be attributed with the SerializationAttribute to be serializable - ISerializable just allows you to custom serialization of your Type).
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Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles] [My Blog]
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Interfaces are the public methods/properties/events a class must have (exact same signature) in order to implement them.
For example, any class that implements IDisposable MUST implement 'public void Dispose()' method
You can cast any object into any interface it implements making it useful, among other many things, as a way of achieving polymorphism (dont know if thats the exact term in english).
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Skynyrd wrote:
For example, any class that implements IDisposable MUST implement 'public void Dispose()' method
That's not the only option. You can also implement it explicitly, which is how the disposable pattern recommends:
public class MyDisposableClass : IDisposable
{
public MyDisposableClass() {}
protected virtual void Dispose(bool disposing)
{
if (disposing)
{
}
}
void IDisposable.Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
~MyDisposableClass()
{
Dispose(false);
}
}Skynyrd wrote:
You can cast any object into any interface it implements making it useful
That's not correct, either. You can cast any managed object to any managed interface it implements, but you can also cast any proxy object to any interface it may not implement in managed code if it is attributed with the ComImportAttribute. This tells the CLR to QI (COM's QueryInterface for the interface based on its compiler-generated IID (an interface GUID) - which should never be the case - or its GuidAttribute value (to remain fixed) - which is the highly recommend way of declaring interface (so that the IID never changes; for COM interop, this is required to actually refer to the interface your trying to QI for).
I know that's not the simple case the original poster was asking for, but it's still the correct information.
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Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles] [My Blog]
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An interface is somehow like an abstract base class as it defines a set of methods, properties, events and/or indexers, which have to be implemented by inheritors, but doesn't provide an implementation for its members.
The big advantage of interfaces is the allowed multiple inheritance. So classes and structures can implement multiple interfaces and interfaces themself can inherit from multiple other interfaces.
If a class or structure implements an interface, it has to provide an implementation for all the interface members. E.g. if a class implemnts the IDisposable interface, it has to provide a Dispose method.
Does this help?
www.troschuetz.de
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Certainly.
Interfaces are "standards" which every class implementing them has to meet.
If you had an interface "ICar", the classes "Ford" and "FIAT" both would implement "ICar".
Why? Because every car has to implement ICar, since ICar is the standard for cars.
This is so every car feels the same.
Even if you practised on a FIAT, the Ford still has Accelerator, Brakes, Engine, Transmission... which are defined in ICar.
If you choose to implement an Interface, you cannot implement only part of it - you have to go the whole way (the interface would be useless otherwise).
Say you want to create an application which is extensible via PlugIns. You would then define an interface for you plugin and application, so every plugin anyone writes fits into the "socket" on the application.
So, within that application, you can call "sendMessage" on every Plugin - but one Plugin may send the message via email, another one via FTP ...
I think you get the general idea 
Cheers
Sebastian
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I'm trying to create a 2nd AppDomain for handling remotingserver stuff. What am I doing wrong here:
AppDomainSetup info = new AppDomainSetup();
info.ApplicationBase = "file:///" + System.Environment.CurrentDirectory;
AppDomain dom = AppDomain.CreateDomain("DataHandler", null, info);
BindingFlags flags = (BindingFlags.Public | BindingFlags.Instance | BindingFlags.CreateInstance);
ObjectHandle objh = dom.CreateInstance("CommunicationServer", "CCommunicationServer", false, flags, null, null, null, null, null);
Object obj = objh.Unwrap();
CCommunicationServer h = (CCommunicationServer)obj;
h.BeginRemoting();
Then I have the remoting server class which I have compiled as a dll:
public class CCommunicationServer : MarshalByRefObject
{
...
}
When I call dom.CreateInstance("...); I get an exception saying: Could not load type CCommunicationServer from assembly CommunicationServer.
Have I understod something wrong here? Should I use AppDomain.Load() or something? Can you please give me a basic example how to get a 2nd AppDomain running.
Thank you.
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First of all, don't prefix your classes with "C". This is inconsistent with the .NET Framework. A good RAD (rapid application development) environment requires consistency. Read the Naming Guidelines[^] for more details. Hungarian notation is obsolete in the .NET Framework naming conventions (and CLI).
Is the CCommunicationServer class the fully-qualified class name? If it is defined within a namespace you must specify that as well. If you're getting a TypeLoadException then that indicates the assembly was loaded but the Type (your class) was not found. AppDomain.CreateInstance throws the FileNotFoundException when the assembly isn't resolvable. The documentation indicates as much.
You might also consider setting the AppDomainSetup.ConfigurationFile property to allow your application to use a .config file. These are more important than using them for Remoting configuration data as I mentioned in a previous post to you. You can also redirect assembly bindings and configure other runtime settins as well. It definitely leaves you open to other possibilities. And, once again, configuring your remoting server via a configuration file is far more flexible than hard-coding it. Read about the Remoting Settings Schema[^] in the .NET Framework SDK for more details.
This posting is provided "AS IS" with no warranties, and confers no rights.
Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles] [My Blog]
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Thanks. Adding the namespace did the trick. My next problem  is firing events from the 2nd appdomain to the "main" domain, and I'd like to know is that even possible, so that I don't waste my time?
And thanks also for the naming guidelines, I will check in to that. And now that I have the 2nd appdomain running, I will modify the remoteserver so that it'll use the configuration file. BTW, why is it so important to use AppDomainSetup.ConfigurationFile?
Thank you.
Here: ![Rose | [Rose]](https://www.codeproject.com/script/Forums/Images/rose.gif) Have a rose for you trouble
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It is possible. And it's called... .NET Remoting. Remoting is a managed RPC framework for communicating between context boundaries. Separate AppDomains - whether they are in the same process or not - are most definitely context boundaries.
Fortunately, the .NET Framework implements a default cross-domain remoting channel but it's pretty limited. Some in-depth research into remoting should mention this, but you should find more information in Ingo Rammers "Advanced .NET Remoting". See http://www.ingorammer.com[^].
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Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles] [My Blog]
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how can u find out the program files directory in .NET eg (C:\Program Files)
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System.Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles)
"I think I speak on behalf of everyone here when I say huh?" - Buffy
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i do not know how to describe , my English is very poor, so i call it "code pucker" .
Like the vs.net's IDE , you can click the node which at left side of every "{" to pucker the code .
i am very interesting on it , but i am a beginner, i try to read the source code of SharpDevelop, but i feel it was diffcult to me, can you help me?
thanks very much!
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has anyone seen a really great piece of auto complete code? For those of you who dont know what autocomplete is :
'Suppose u have a combobox in which u have a few items added to the collection like "Hello", "Hi" , "Doggone". Now when u type "H" in the box the combobox automatically fills in "ello" for you. So u dont have to type the entire word.
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i have a checkbox on my form and i have written a few lines of code on the checkbox.checkchanged event which fires everytime u check or uncheck the box. This works fine till u check it by clicking on it at runtime but the event doesnt fire when I type checkbox.checked = true. How cn i make the event fire through code..
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If checkbox.Checked is already true, and you write the checkbox.checked = true, then checkbox.checkchanged will not fire, since the checkState is not being changed, Otherwise it will fire.
Check using the statement like
this.checkbox.Checked = !this.checkbox.Checked;
BTW, If you want to call the eventHandler from any where else call like below
this.checkBox1_CheckedChanged(this, new System.EventArgs());
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hi jay,
my code doesnt seem to fire when i type checkbox1.checked = true; even thouhg my checkbox state is false.
please subscribe to this thread so i can reply
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Hi Mridang,
First of all, please go through the msdn documents CheckBox.CheckedChanged[^]
It should fire. There is no bug in the .net, concerning this.
As I said in my previous post, check using again.
this.checkbox.Checked = !this.checkbox.Checked;
or
private void ChangeCheckBoxState(CheckBox cbx)
{
cbx.Checked = !cbx.Checked;
System.Diagnostics.Debug.WriteLine("checked state transformed to " + this.checkBox1.Checked);
}
private void checkBox1_CheckedChanged(object sender, System.EventArgs e)
{
MessageBox.Show("Check Changed");
}
You can explicitly also call the event handler, just to reconfirm as
this.checkBox1_CheckedChanged(this, new System.EventArgs());
I would also advice you to prepare a simple demo project to check the above phenomenon.
Regards,
Jay.
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anyone knows how I can change the window class name of a winform?
now I get something like "WindowsForms10.Window.0.app4"
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Override CreateParams in your derivative class and set the CreateParams.ClassName. If this is not an existing Window class, you'll need to P/Invoke RegisterClassEx and call it prior to creating any instances of your new control class. See http://pinvoke.net/default.aspx/user32.RegisterClassEx[^] for more information.
This posting is provided "AS IS" with no warranties, and confers no rights.
Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles] [My Blog]
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Hi
I have a problem regarding events of form controls especially in the order in which they are raised on different operating systems.
For example:
I have LostFocus event for a ListView and GotFocus event for TextBox. When the user navigates from ListView to TextBox we are unable to determine the order in which these two events are fired. We noticed that in some operating systems LostFocus of ListView is raised first but in some other systems GotFocus of TextBox is raised first. This is an example to present the problem.
Can somebody help me out how to control this order on different OS/System? I want to raise the events in a same order though user uses my program on different machines so that I can program accordingly.
Thanks in advance.
Sundar
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try using Validated and Enter events in place of LostFocus and GetFocus events respectively;
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Hi! I'm a 14 year old programmer that has programmed in 4 other languages so far other than C#. I'm creating an IDE for one of the languages, and was wondering how I would go about doing syntax hilighting in a Rich Text Box. Sorry, please
explain it in a way a 14 year old half-newbie at C# could understand! Thanks in advance!
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Akin to my last reply to the question below yours, this site contains hundreds of articles, but you need to search first. Research is just part of development.
Adding to that, the RichEdit control is not the best option. You get inundated in overriding the behavior of the control when defining your own edit control (or reusing an existing control available in third-party controls, either free or commercial) gives you far more capabilities. The RichEdit control itself isn't very flexible. To be more flexible you have to P/Invoke a whole slew of native functions and define several interfaces for interop. In both cases, your marshaling a lot of data between native and managed code. For this reason, I recommend you use Managed C++ for a mixed-mode assembly (containing both native and managed code). This will optimize the calls - especially in the upcoming release of Visual Studio 2005 (more specifically, Visual C++ 2005 using the /clr switch).
For more information about the RichEdit APIs and interfaces, read Rich Edit Controls[^] in the Platform SDK documentation.
This posting is provided "AS IS" with no warranties, and confers no rights.
Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles] [My Blog]
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Hi,
I want to add a Column containing Command Buttons to ListView Control... is it even possible... can i have some sample code...
thanx in advance
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