Re: Windows Form Designer - C# Discussion Boards

29-Sep-02 20:59

im not sure, i presume it reads from where ever the current position, set in stream.Seek to the end of the file, but i cant swear to it.

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"All programmers are playwrights and all computers are lousy actors."

VFW in C#

Jarrett Vance27-Sep-02 10:43

Jarrett Vance

27-Sep-02 10:43

Is it possible to call upon video for windows VFW in C#? Is there any existing code for compressing an AVI in C#? Thanks for any help or links you can provide.

Re: VFW in C#

Stephane Rodriguez.27-Sep-02 22:29

Stephane Rodriguez.

27-Sep-02 22:29

Anything you do with WIN32 and C/C++ is possible in C# thanks to interop.

When you know the method signature, you just need to declare it in your code with a [DllImport("dllname")] attribute like in ::SendMessage :

[DllImport("user32.dll", CharSet=CharSet.Auto)]
public static extern IntPtr SendMessage(IntPtr hWnd, int msg, int wParam, IntPtr lParam);

Even more interesting is that in your case there are COM components. And the VS.NET IDE automatically imports their type-library, wrap interfaces and makes them look like any namespace to you. That's what you get for instance when you need integration with Internet Explorer, MS Office, ...

Now about DirectShow itself, this SDK has both COM Components and simple low-level APIs. Just help yourself. Below is 2 CP articles about it :
DirectShow media player[^]
DirectShow.NET[^]

You've got an introductory article about DirectShow in MSDN Mag - july 2002[^].

if you start putting in too manay features, it no longer remains useful for beginners
quote in a CP article comment, shiraz baig

Re: VFW in C#

Daniel Strigl29-Sep-02 20:15

Daniel Strigl

29-Sep-02 20:15

Take a look on DirectShow.NET.

--
Nice greets, Daniel.

Windows Form Designer

Nnamdi Onyeyiri27-Sep-02 8:38

27-Sep-02 8:38

Does anyone know how to make my control such that when it is displayed in the windows form designer, the grid does not appear over it???

[edit]
oh, and im not gonna ask if there is something specific i have to do to my collectionbase derived class, to make the windows forms designer use the collection properly Mad | :mad:

[/edit]

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"All programmers are playwrights and all computers are lousy actors."

leppie27-Sep-02 9:15

27-Sep-02 9:15

Nnamdi Onyeyiri wrote:
oh, and im not gonna ask if there is something specific i have to do to my collectionbase derived class, to make the windows forms designer use the collection properly

You just need to implemenet an indexer Smile | :)

We had plenty disscussions about that during the last week. Have a look at the CollectionEditor class for more details, I'm still trying to figure out how to add multiple types, it sure did look easy Smile | :)

Cheers

PS: Where have u been?

Give them a chance! Do it for the kittens, dear God, the kittens!
As seen on MS File Transfer: Please enter an integer between 1 and 2.

Nnamdi Onyeyiri27-Sep-02 9:26

27-Sep-02 9:26

public class EBGroupCollection : CollectionBase
public EBGroup this[int index]
   {
    get
    {
     return (EBGroup)this.List[index];
    }

    set
    {
     this.List[index] = value;
    }
   }

   public EBGroupCollection()
   {
   }

   public void Add(EBGroup value)
   {
    this.List.Add(value);
   }

 }

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"All programmers are playwrights and all computers are lousy actors."

Maciej Pirog27-Sep-02 9:48

Maciej Pirog

27-Sep-02 9:48

I just don't get those strange indexers.

Nnamdi Onyeyiri wrote:
EBGroup this[int index]

It looks like the good old C++'s operator[]

Ñ There is only one MP Ð

leppie27-Sep-02 9:55

27-Sep-02 9:55

Yes , the quote button is gone, they are the same Smile | :)

Give them a chance! Do it for the kittens, dear God, the kittens!
As seen on MS File Transfer: Please enter an integer between 1 and 2.

Nnamdi Onyeyiri27-Sep-02 10:13

27-Sep-02 10:13

that code is what i am using, and that code, is the code that isnt working Poke tongue | ;-P

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"All programmers are playwrights and all computers are lousy actors."

leppie27-Sep-02 10:38

27-Sep-02 10:38

Oops,

make sure the type you are adding has a default constructor, as allways Smile | :)

Give them a chance! Do it for the kittens, dear God, the kittens!
As seen on MS File Transfer: Please enter an integer between 1 and 2.

Nnamdi Onyeyiri27-Sep-02 11:17

27-Sep-02 11:17

yer, it/they does/do.

EBGroup is a class, with another collection, i dentical to the other one, except for EBItem [also a class]. can i not use classes?

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"All programmers are playwrights and all computers are lousy actors."

leppie28-Sep-02 1:53

28-Sep-02 1:53

Nnamdi Onyeyiri wrote:
EBGroup is a class, with another collection, i dentical to the other one, except for EBItem [also a class]. can i not use classes?

Yes you can! I would sugest you make a few small skeleton classes to see where the problem lies...start at the other container iow that 1st collection you mentioned.

Good luck Smile | :)

Give them a chance! Do it for the kittens, dear God, the kittens!
As seen on MS File Transfer: Please enter an integer between 1 and 2.

Tomas Petricek27-Sep-02 11:08

Tomas Petricek

27-Sep-02 11:08

leppie wrote:
We had plenty disscussions about that during the last week.

Wink | ;)

Nnamdi Onyeyiri27-Sep-02 12:03

27-Sep-02 12:03

leppie wrote:
PS: Where have u been?

what do you mean?????? [just noticed this bit]

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"All programmers are playwrights and all computers are lousy actors."

leppie27-Sep-02 13:36

27-Sep-02 13:36

Nnamdi Onyeyiri wrote:
what do you mean

Havent seen many posts from you lately, was just wondering? Dead | X|

Give them a chance! Do it for the kittens, dear God, the kittens!
As seen on MS File Transfer: Please enter an integer between 1 and 2.

Interfaces

Nick Parker27-Sep-02 7:46

27-Sep-02 7:46

Are there any good articles that anyone is aware of that explains in detail specifically what interfaces are and how they are used in C#. Thanks. Smile | :)

Nick Parker

The goal of Computer Science is to build something that will last at least until we've finished building it. - Unknown

Paul Riley27-Sep-02 7:59

Paul Riley

27-Sep-02 7:59

This thread: When to define interfaces[^] had some interesting facts and opinions on the subject.

Paul

Nick Parker27-Sep-02 8:15

27-Sep-02 8:15

Thanks Paul,
A little further down in that discussion John Burton makes a comment [^] about them which makes me think they are used to describe a virtual function as we do in C++. However with your[^] comment they appear to implement the flavor of inheritance to a class. Both of which make some sense, however I would really like to read a full article where they are described in great detail. Thanks for the link though. Smile | :)

Nick Parker

The goal of Computer Science is to build something that will last at least until we've finished building it. - Unknown

Paul Riley27-Sep-02 8:26

Paul Riley

27-Sep-02 8:26

The problem is that C# is new enough that it is all a matter of opinion. To offer a single article (which I don't have, or I would do anyway) would be to offer only one person's opinion.

To my mind, neither viewpoint that you've picked out is strictly wrong, nor are they mutually exclusive. An interface is sort of like an abstract class for a language that otherwise doesn't allow multiple inheritance. So in a way, it is like offering a set of virtual functions.

The most useful purpose of this is to offer a flavour of inheritance to the class.

Does that make sense? (it is Friday night!)

Paul

Nick Parker27-Sep-02 8:42

27-Sep-02 8:42

Paul Riley wrote:
(it is Friday night!)

Don't tell me you shut down on Friday night....I get it, however just because C# is a new language doesn't mean there isn't anything more than someones opinion Dead | X|

As soon as I find out more about them I may just have to put together a little or big article than can clear this all up for us. Smile | :)

Go enjoy your Friday night, not too much though, otherwise Saturday will hurt you. Wink | ;)

Nick Parker

The goal of Computer Science is to build something that will last at least until we've finished building it. - Unknown

Nick Parker27-Sep-02 8:52

27-Sep-02 8:52

Good news, I found a really good article[^] that pretty much clears it up for me, take a look. Smile | :)

Nick Parker

The goal of Computer Science is to build something that will last at least until we've finished building it. - Unknown

Paul Riley27-Sep-02 10:16

Paul Riley

27-Sep-02 10:16

That is a good article, well found.

I do think it could be better though Smile | :)

. What an interfaces article needs is a single practical example: this is an interface, these are two classes that might implement this interface. What this does is say: this is an interface, and this is how you use one that already exists, proving how difficult it is to find a practical use for interfaces (the StringList example is pointless).

Just thinking aloud. I might be tempted to work on this when my workload calms down over the next few weeks and I get to finish the one I'm already working on. Smile | :)

Paul