Re: C# - my first stupid question - C# Discussion Boards

Re: C# vs VB.NET. Facts not opinions please :)

15-Mar-02 7:42

Christian Graus wrote:
I've discovered tonight that you can use pointers in C#, although I'm not yet sure of the implications of using the unsafe keyword.

unsafe code does compile to IL, but it is unverifiable; so you need a higher permissions set to run the code. The same goes for P/Invoke.

James

Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978

James T. Johnson15-Mar-02 7:56

C# - my first stupid question

15-Mar-02 7:56

David Wengier wrote:
I guess the first question is can you do either of these

C# has overloaded the += and -= operators for events so that you can add and remove event handlers at runtime. This is also the only way that C# lets you add event handlers.

The AddHandler statement that you see in VB is VB specific and is part of the VB.NET language. However if you can get access to the underlying EventHandlerList there is an AddHandler method on that you can use. An Events property of type EventHandlerList is exposed on the System.ComponentModel.Component class and its derivatives as well as the System.Web.UI.Control class.

David Wengier wrote:
Are there things that one does that the other doesnt?

VB lets you assign events with the Handles keyword; it is also easier to do Late Binding with VB but you can accomplish the same with some Reflection in C# (or any .NET language).

C# lets you overload operators, and create/use indexers (a property on a class so that you can treat an instance of the class like an array ie foo[3]).

Someone on the DOTNET list noticed that the IL that VB.NET produces has a lot of NOPs in its code generation. While it makes the IL a little bit bigger the JIT will compile those away to nothing.

HTH,

James

Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978

Christian Graus14-Mar-02 23:27

14-Mar-02 23:27

All the exmaples I see are making one fat .cs file - what is the equivelant of #include, so I can see the contents of one file from another ?

Thanks

Christian

The tragedy of cyberspace - that so much can travel so far, and yet mean so little.

"I'm thinking of getting married for companionship and so I have someone to cook and clean." - Martin Marvinski, 6/3/2002

James T. Johnson15-Mar-02 7:40

15-Mar-02 7:40

You don't. C# -- like Java -- doesn't look for dependencies until the linking stage (if you could call it that).

main.cs

using System;

public class Test
{
  public Test() { }

  public static void Main(string [] args) {
    Foo f = new Foo();
    f.SayHello(); 
  }
}

foo.cs

using System;

public class Foo
{
  public Foo() { }
  public void SayHello() {
    System.Console.WriteLine("Hello Chrstian!");
  }
}

That will work just fine, assuming both files are in the compiling process.

James

Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978

Christian Graus15-Mar-02 9:11

15-Mar-02 9:11

Why might it not work ? I did this last night and still got nowhere. If I create a file and save it, do I need to add it to the project somewhere as well ?

Christian

The tragedy of cyberspace - that so much can travel so far, and yet mean so little.

"I'm thinking of getting married for companionship and so I have someone to cook and clean." - Martin Marvinski, 6/3/2002

James T. Johnson15-Mar-02 9:26

15-Mar-02 9:26

Christian Graus wrote:
If I create a file and save it, do I need to add it to the project somewhere as well ?

Yes, it will have to be added to the project or it won't get compiled. How did you go about creating a file and saving it? If you go through the IDE it should be added to the project for you.

How I add a new class: Right click my project in the Solution Explorer, choose Add then Add New xxxxx (class, component, windows form, etc).

Ah! Just a shot in the dark, do the namespaces match between your two files? Come to think of it, my example didn't have a namespace for foo.cs Blush | :O

If you change the namespace you can let the IDE help you a little, right click on the project and choose Properties, then change the Default Namespace to the base namespace you use.

HTH,

James

Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978

Christian Graus15-Mar-02 9:24

15-Mar-02 9:24

No, I didn't do it quite like this, but I did it through the IDE. I made sure my namespaces matched, but I'll try it fllowing what you said and see how it goes.

Thanks.

Christian

The tragedy of cyberspace - that so much can travel so far, and yet mean so little.

"I'm thinking of getting married for companionship and so I have someone to cook and clean." - Martin Marvinski, 6/3/2002

Eric Gunnerson (msft)15-Mar-02 14:28

Eric Gunnerson (msft)

15-Mar-02 14:28

If you're compiling as part of the same project, you don't need #include; the compiler can automatically access the classes in all the files that are compiled together.

If you're compiling into separate assemblies (aka dlls), you'll need to add the referenced one either to the project or using /r on the command line.

Christian Graus15-Mar-02 14:33

Byte representation of integer

15-Mar-02 14:33

Thanks - it seems the way I added the file did not make it part of the proejct, I did the exact same thing this morning, but added the class by right clicking in the class view and it all worked fine.

Christian

The tragedy of cyberspace - that so much can travel so far, and yet mean so little.

"I'm thinking of getting married for companionship and so I have someone to cook and clean." - Martin Marvinski, 6/3/2002

14-Mar-02 17:29

Anybody can tell me how do I get the byte representation of an integer?
E.g. int iValue=500, then the byte representation is 00 00 01 F4.

Thanks.

Re: Byte representation of integer

Serge Krynine14-Mar-02 17:58

Serge Krynine

14-Mar-02 17:58

int iValue = 500;

byte byte0 = iValue; // byte0 is 0xF4
byte byte1 = iValue >> 8; // byte1 is 0x01
byte byte2 = iValue >> 16; // byte2 is 0x00
byte byte3 = iValue >> 24; // byte3 is 0x00

Custom Controls for ProgressBar

BLaZiNiX14-Mar-02 16:39

BLaZiNiX

14-Mar-02 16:39

Anybody know how can I make a Custom Controls for a ProgressBar to add these functionnalities : SetBkColor, SetBarColor, FlatStyle ?

Thanks

Update status of toolbar buttons

paulb14-Mar-02 13:36

paulb

14-Mar-02 13:36

You can update the enabled/disabled status of menu items using the Popup event for the menu, but how do you update the status for toolbar buttons?

Re: Update status of toolbar buttons

James T. Johnson14-Mar-02 13:45