|
 Can a windows service capture HID input events?
I need to capture HID input from a remote control. I have done this and was successful in a windows application by overriding WndProc.
I need to be able to do this in a service and can't seem to get anything? Does a service have a hidden top level window I can override? Is there a way to do this?
Mary
|
|
|
|
|
Hey,
i am trying to develop a small program taking advantage of .NET Remoting.
I have a button which i want to Start and Stop the Server with.
But my problem is that I cant really find any information about how to stop the Server.
I simply start the Server by doing the following:
RemotingConfiguration.Configure("theconfiguration.config");
But then i dont know how to stop the Server again when pushing the button.
Can anyone help me ?
I can see that if i instead of using a configuration file, set it all up directly in the code there is the ChannelServices.RegisterChannel and the ChannelServices.UnregisterChannel.
But will this be the correct way to do it if i want to start and stop the Server ?
Or will i have to etc. make a new application domain and run the server there and then destroy it when i want the Server to stop ?
How should it be done ?
Hope someone can help me
Best regards
Martin
|
|
|
|
|
|
I am trying to sort out the difference between these terms as they seem to be thrown around interchangebly. But indeed are they really different concepts or is casting basically helpful in describing boxing/unboxing?
Casting defined: objects of one type converted to objects of another type
Boxing defined: 1 - casting a value type into a reference type 2 - casting to an object
Unboxing: casting the reference type back into a value type
And sort of a separate question, but how can I figure out the rules of casting.... in other words I expected to able to do this. Is the reason it cannot be done because the variable i2 is not an object?
int i2 = 5;
string s2 = "";
s2 = (string)i2;
However you can do this, and myShort is not an object.
short myShort;
int myInt = 500;
myShort = (short)myInt;
So I am a bit confused about when I can try to cast vs box!
-- modified at 21:04 Saturday 28th January, 2006
|
|
|
|
|
Boxing is casting a value type to a reference type.
Unboxing is just the reverse.
You want to avoid boxing whenever possible. There is a HUGE performance penalty for both box and unboxing.
An integer, or just about snything else for that matter, can't be cast to a string. Each type has it's own .ToString() method to return a string representation of the object.
int i2 =5;
string s2 = i2.ToString();
Value types CAN be cast to other values types. All that's required is a little change in the representation. Your example works because a short (16-singed integer) can be converted to an int (32-bit signed integer, just by widening the field. There's no loss of data.
Are there any hard and fast rules to casting? No, not really. It depends on the type and what it's being converted to.
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
|
|
|
|
|
Regarding my terminology question... It seems like boxing is a specific way of casting (casting value type to reference type)? I just seem to find the two terms thrown around a lot and I want to make sure I am using them correctly.
I think I am getting the point of why I could not cast s2 = int(i2) ?? But to be sure, this is my take after reading responses: (Very simply put however!)....Basically string and int types are derived from the same parent class, so I cannot cast. Instead if I need to do the casting (correct term?), then I do this in C# by using the ToString method ( and in the background C# boxes the value (i.e. makes it an object )).
I hit the books and found various definitions for boxing/unboxing and only one definition for casting. But it never really helped me to know why I could not cast an int to a string. So thank-you for the help. It seems like some of the casting can be trial and error and the compiler in most cases will help you out; but if you care to look at the where the classes are coming from (the parent class) then you can figure out if the cast might work?
Various definitions of boxing (choose your favorite one  )
1) Boxing: So that common operations can be performed on both reference types and value types, each value type has a corresponding hidden reference type. This is created when it is cast to a reference type. This process is called boxing.
2) Boxing: Value types are allocated on the stack by default, but they can always be converted into a heap-based reference-type object, called boxing.
3) Unboxing: The reverse of boxing is of course unboxing, which means that you can convert a heap-based reference-type object into its value-type equivalent…
4) Boxing and unboxing are the processes that enable value types (e.g., integers) to be treated as reference types (objects). The value is "boxed" inside an Object, and subsequently "unboxed" back to a value type.
5) Boxing At its simplest, boxing is the conversion of a value type to a reference type. The reciprocal case is when a reference type is unboxed back to a value type.
6) Boxing: Thus, a value type is “boxed” inside an object (when an object reference refers to a value type, a process know as boxing occurs).
Casting Definitions
Casting: Object of one type can be converted to objects of another type… It can be implicit or explicit.
-- modified at 13:43 Sunday 29th January, 2006
|
|
|
|
|
LuluSailor wrote: It seems like boxing is a specific way of casting (casting value type to reference type)?
No, it's not. Look at the term itself - BOXING. What your doing is pretty close to putting a type in a box so that it can be contained and manipulated as the box type, not the type that's in the box.
Casting is a conversion of a type to another, SIMILAR, type. That's why you can't cast an int to a string. They're nowhere near similar in their functionality.
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
|
|
|
|
|
First let's look at the two different kinds of data types:
Value type: A simple data type that is stored as-is, like an int.
Reference type: A pointer (which is basically an int) that points to memory allocated on the heap, that contains the actual data.
Casting reference types in .NET is somewhat different than in most other platforms. The objects in .NET contains their own datatype information, so the type of the reference only determines how you use the object, not the actual type of the object. This means that in .NET you can only cast a reference to the actual class or one of its base classes, not to some completely different class.
Then let's look at the different ways of casting:
:: Casting a value type to another value type. Most numeric value types can be casted to other numeric value types. This is actually more of a conversion than a cast.
:: Casting an object to any of its base classes, for an example casting an HtmlButton to an Object. This only changes the type of the reference, leaving the actual data unchanged.
:: Casting an object from a base class to the actual class or one of the inherited classes on the way, for an example casting an Object reference that points to an actual HtmlButton object from Object to HtmlControl.
:: Boxing a value type into a reference type, for an example casting an int to an Object. This will allocate memory on the heap where an object structure containing the int is stored, and the result is an Object reference that points to that memory structure.
:: Unboxing a reference type to its value type, for an example casting from an Object to an int. This will retrieve the data from the memory structure and release the memory used on the heap. Unboxing can only be done to the exact value type that the object contains, no other value type.
---
b { font-weight: normal; }
|
|
|
|
|
Hello all,
I have search a loooooooot in Google to get a nice neat way to convert MS Word Document into plain text file using C#. I did not get any solution. It would be great if anyone can help me with any snippet or suggession.
Thanks to all
Emran
|
|
|
|
|
Check out wvWare library .wv is a library which allows access to Microsoft Word files. It can load and parse Word 2000, 97, 95 and 6 file formats.
Use wvText - to convert word document to plain text.
http://wvware.sourceforge.net[^]
DevIntelligence.com - My blog for .Net Developers
|
|
|
|
|
Thank you sooooo much.
Emran
|
|
|
|
|
Hi all ,
I have a byte array which includes ascii data.
What is the best way to transfer it to hex ?
By the way , How can I show this data within datagrid ?
Thanks very much
|
|
|
|
|
I am trying to write a simple class, my own CheckBox using my own "bitmap checkmarks", derived from UserControl. I want to add this to my Toolbox and use it in windows forms applications. Not only do I need to understand how to properly write this, I also need to know how to properly embed the bitmap resources in the control.
Can anyone direct me to a good tutorial?
Thanks!
Mark
|
|
|
|
|
|
I should check if user’s mail exists or not, when she/he enters in my web application. But in asp.net we can just send an email with classes in the System.web.mail namespace. But as I mentioned, it is vital in my web application that user’s mail is a real mail. So I should check it if it is real or not (except its format).
Please instruct me to solve my problem with mail checking.
Thanks a lot.
Thanks Rastegar
|
|
|
|
|
There is no way that you can automatically check for certain if the mail address exists.
You can ask the mail server if it will accept the mail address, but that is not a guarantee that the address is correct. Large mail servers (for an example hotmail) will accept any address, as it's too much work to check the address both before and after recieving a mail.
The only way that you can be certain that the address works is if you send a mail to the user, that contains an address where they can confirm the address.
---
b { font-weight: normal; }
|
|
|
|
|
Check out MailChecker [^]. MailChecker is a DLL that lets you check the validity of an Email address by querying the mail server responsible for the email address and asking it via SMTP if the email is valid.
DevIntelligence.com - My blog for .Net Developers
|
|
|
|
|
|
I'm designing a class library Foo that will contain several classes (Bar, Derf, etc.). Foo will be released as the single assembly Foo.dll and will exist in the namespace MyCompany. IOW, clients of the Foo library will write code like this:
using MyCompany.Foo;
...
Bar bar = new Bar();
...
What's the recommended method for laying out the Foo solution?
Bar.cs resides in the solution's top level folder and contains:
namespace MyCompany {
namespace Foo {
public class Bar {
...
}
}
}
Bar.cs resides in the in the solution's top level folder and contains:
namespace MyCompany.Foo {
public class Bar {
...
}
}
Bar.cs resides in the folder /MyCompany/Foo/ within the solution (a la Java) and contains the content specified in either (1) or (2). I know .NET doesn't infer namespace definition and membership from directory layout, but is this the recommended method for organizing source code?
- Something else?
Thanks!
/ravi
My new year's resolution: 2048 x 1536
Home | Music | Articles | Freeware | Trips
ravib(at)ravib(dot)com
|
|
|
|
|
I think that you should name the assembly after the namespace, e.g. MyCompany.Foo.dll. That will follow the way Microsoft names the assemblies in the framework, for an example the System.Runtime.Serialization.Formatters.Soap namespace is in System.Runtime.Serialization.Formatters.Soap.dll.
There is no reason to nest the namespaces if they only contain a single namespace. Stick with the second layout whenever you can.
If you have a large number of files, you can put them in separate folders to keep track of them, otherwise i think that you should just name the files after the namespace, e.g. Foo.Bar.cs.
Note: In C# you can have several classes in a file. It's not like Java where (AFAIK) you need a separate file for each class.
---
b { font-weight: normal; }
|
|
|
|
|
|
Do you, or is it bad practice to do this sort of thing: Class A { Class B {} } ? I have never seen any of the book examples show that you ever would do this.
Here is the example I was working on.... the first class Tester code (not commented out) does not compile (error: The name Temperature does not exist in the current context). But below the commented out class Tester code will work because I removed the Values class. Is there a way to get it to work without removing the Values class. ( Please keep in mind, some of this might not be a very practicle example.... i.e. it really does not make sense to have the Values class in the first place!)
*/
using System;
using System.Collections.Generic;
using System.Text;
namespace EnumFreezingInRun
{
// this gives error "The name Temperature does not exist in the current context"
class Tester
{
class Values
{
enum Temperatures
{
WickedCold = 0,
FreezingPoint = 32,
}
}
public void Run()
{
Console.WriteLine("Freezing is: {0}", (int)Temperatures.FreezingPoint);
Console.WriteLine("Wicked cold is: {0}", Temperatures.WickedCold);
}
static void Main()
{
Tester t = new Tester();
t.Run();
}
}
// This does work!
//class Tester
//{
// enum Temperatures
// {
// WickedCold = 0,
// FreezingPoint = 32,
// }
// public void Run()
// {
// Console.WriteLine("Freezing is: {0}", (int)Temperatures.FreezingPoint);
// Console.WriteLine("Wicked cold is: {0}", Temperatures.WickedCold);
// }
// static void Main()
// {
// Tester t = new Tester();
// t.Run();
// }
//}
}
|
|
|
|
|
LuluSailor wrote: Do you, or is it bad practice to do this sort of thing: Class A { Class B {} } ?
I wouldn't say it was bad practice. Only that there are a limit number of situations that would warrant this.
The only one I can think of is to have the enumerator (a class deriving from IEnumerator) as an inner class of the one that it enumerates (which will normally implement IEnumerable).
ColinMackay.net
"Man who stand on hill with mouth open will wait long time for roast duck to drop in." -- Confucius
"If a man empties his purse into his head, no man can take it away from him, for an investment in knowledge pays the best interest." -- Joseph E. O'Donnell
|
|
|
|
|
Thank-you for taking the time to answer my question Colin. It did seem that this is not too common, since I did not see it done in examples (class A {class B{}} )
So is there another way to get the code to work, other than remove the pluck out (delete) the Value class from the code? I am just curious how I would get the Temperatures to become available/ or in context without removing the class.
Although - my main concern you have answered, which is how common it would be to define a class within a class. I am still not sure what I am really doing when I define a class within a class. But this might be a bit too advanced for me right now. For now - I will not do it (accidentally or otherwise)!
|
|
|
|
|
Another reason that you may want to define an inner class relies on how you will use B in class A{ class B{} }. If only A uses B and no other class should use B, then a private inner class would work well in that situation.
For example, if you write a class that acts as a binary tree that supports only adding, searching, and removing, then you may never need to expose the class that implements the node in that tree structure. Thus, you could have something like the following incomplete code snippet.
public class Tree
{
public Tree() {
public object Search( object obj ) {
public void Add( object obj ) {
public void Remove( object obj ) {
private class Node
{
public Node( object o ) {
}
}
"we must lose precision to make significant statements about complex systems."
-deKorvin on uncertainty
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
