C# Discussion Boards - CodeProject

Re: How can i...?Please help me please !!!!

10-Oct-05 4:33

snouto wrote:
i just want to do so in robotics.

Then use a language more appropriate for the hardware controller that is manipulating the machine. C# will not compile down to what you want.

snouto wrote:
If you clicked start----> run and you typed the command
ymsgr:sendim?matrix_623
if your messenger is already open it will open for you a private chat window?

Your application must be able to detect that it is already running (search the articles for "single instance application"). Also, your application must expose an interface so a second instance of your app that gets launched can pass parameters to the first instance. Just search the articles and you'll find a few examples.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Brendan Vogt9-Oct-05 23:06

Brendan Vogt

9-Oct-05 23:06

It's Mess with the best,... And not Miss...

Usage of ICloneable

Robert Rohde9-Oct-05 9:55

Robert Rohde

9-Oct-05 9:55

Hi everyone,

this is not really a programming question, but as I made some thoughts about cloning my objects I had an idea and just want to hear some comments on it.

Normally when a class should be cloneable it implements ICloneable like this:

public class TestClass : ICloneable {
   public object Clone() {
      //Do something
   }
}

The nasty thing about this is that everybody who calls Clone will have to do a cast afterwards (assuming the caller wants to do something with the result where object doesn't help).

Do avoid this one could just forget ICloneable and make a typed Clone method:

public class TestClass {
   public TestClass Clone() {
      //Do something
   }
}

Sadly this isn't an option for me because at some places in my code I have an ArrayList which holds objects of several different classes which I all have to clone.

So I came to the idea to instead combine the two methods and do the following:

public class TestClass : ICloneable {
   object ICloneable.Clone() {
      return this.Clone();
   }

   public TestClass Clone() {
      //Do something
   }
}

So now when I use a variable of type TestClass the Clone method will return TestClass, but I can use it also as an ICloneable where I get an object (Truly also having the type TestClass but unknown to the caller).

So what are your thoughts about it? I think this casting problem when using Clone is relatively widespread, but why is everybody using (I refer to the framework and some 3rd party components) just the naiv method?

PS: Why is the result of ICloneable.Clone an object and not ICloneable? I thought the intention of this interface was that the result should be some kind of deep copy of the object and should always have the same type... Confused | :confused:

-- modified at 15:56 Sunday 9th October, 2005

Re: Usage of ICloneable

S. Senthil Kumar9-Oct-05 19:09

S. Senthil Kumar

9-Oct-05 19:09

If only C# supported Covariant[^] return types, then your problem would go away. You'll be able to return TestClass and still implement ICloneable.Clone.

Robert Rohde wrote:
Why is the result of ICloneable.Clone an object and not ICloneable? I thought the intention of this interface was that the result should be some kind of deep copy of the object and should always have the same type..

ICloneable.Clone clones an object, so why should it return ICloneable?

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

Create new dialog from

Gedrain9-Oct-05 9:27

Gedrain

9-Oct-05 9:27

Hello,

i have a problem with my dialogs. When i create a new dialog i use the methode form2.Show(); But when i close the old dialog what was created before the form2 dialog, the form2 dialogs also closes?

how can this be fixed?

greetings

Sander

Dave Kreskowiak9-Oct-05 14:47

9-Oct-05 14:47

This is happening because you closed the startup form for your application.

For example, the common misconception is that a splash screen can be the startup form for an application. You can't do this. When the startup form closes, it takes the application's message pump with it, closing down the entire application.

The startup form of your app should be the main form your application uses for the builk of it's user interface. Any other forms are created, in a heirarchy, from this form and displayed. You can NOT transfer the application's message pump from form to form.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Gedrain9-Oct-05 14:49

Gedrain

9-Oct-05 14:49

How can i start the new form as a new application then because that is what i want then.

greetings

Sander

Dave Kreskowiak10-Oct-05 4:26

10-Oct-05 4:26

This[^] might help you out. Just remember to change the startup type in your project properties to Sub Main, instead of whateverForm.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Running a batch file in a process from C# code in Windows98 at startup

S. Senthil Kumar9-Oct-05 19:12

S. Senthil Kumar

9-Oct-05 19:12

You need to run the message pump for the other dialog on a separate thread. Something like

void ShowSecondDialog()
{
   new Thread(new ThreadStart(RunMessagePump)).Start();
}

void RunMessagePump()
{
   Application.Run(new Form2());
}

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

factorial program

johnjsm9-Oct-05 8:34

johnjsm

9-Oct-05 8:34

Hi,
I have just started to learn c# and I need to write a program that gets the factorial of a number using a "for" loop. Could anyone help me as i'm having a hard time trying to write it.
thanks

Re: factorial program

Robert Rohde9-Oct-05 8:47

Robert Rohde

9-Oct-05 8:47

Sounds like homework... but I think I have a good day... Wink | ;)

public long Factorial(long number) {
long result = 1;
for (int i = 2; i <= number; i++)
result *= i;
return result;
}

Re: factorial program

Anonymous9-Oct-05 20:52

Anonymous

9-Oct-05 20:52

how sad

Bilal Farooq9-Oct-05 7:29

Bilal Farooq

9-Oct-05 7:29

I have made a C# .NET 2002 based exe which I want to run at the startup of system which is Windows 98 based. Now I added the exe name in HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run so that it could be run whnever the system starts.

This exe is supposed to run a batchfile (which is placed in the same location where the exe is) as the exe starts running. Now I tested it in the debug mode and it works fine (i.e properly runs the batch file in new process ) but whn this exe is executed frm startup the exe starts running but can't run the batch file.

Can anyone tell me what wrong I am doing. Do I have to set the directory name of this exe in the registry or what?

Thanks
Bilal

Bilal Farooq

Re: Running a batch file in a process from C# code in Windows98 at startup

Dave Kreskowiak9-Oct-05 14:43

Can't get Big Arrow on small Line

9-Oct-05 14:43

Without seeing your code, it's a little difficult to tell you what you're doing wrong. But, I can take an educated guess at it.

The standard problem with this is that you're not using a fully qualified path to find the file you're trying to run. You're probably just specifying something like myBatchFile.bat, assuming that that file will be in the current directory. This is almost always the case and a very bad assumption to make. You show never assume that the current directory is whatever you think it is. Instead, always(!) build a complete path to to the file you want, then use that full path in your command line that you want to execute.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Anonymous9-Oct-05 7:01

Anonymous

9-Oct-05 7:01

Here's some code:

void DrawLine(Graphics g)
{
Pen p = new Pen(Color.Blue, 2);
p = c_xy.GetNextPen(); //returns an index of an array of Pens in
//a generic class, (i.e. Pen p1[0]..)
//different Color, different Font
g.DrawLine( p, x1, y1, .....)

How can I draw a line with an arrow or triangle on the end so that it
is obviously visible, that is it looks like an arrow on the end of a line
and not a "sharpened pencil".
I've read a bit of the MSDN and messed around with some code but can't seem to sort out this LineCap/Arrow/Triangle stuff. Not very clear to the novice...thanks

Re: Can't get Big Arrow on small Line

Robert Rohde9-Oct-05 8:58

Robert Rohde

9-Oct-05 8:58

Hi again,

if the predefined LineCap constants are too small for you, then you can define a CustomLineCap (namespace System.Drawing.Drawing2D) by yourself. There is already one implementation in the .Net framework which draws an arrow of selfdefined size.
So when you create your pens instead of assigning the EndCap/StartCap properties do the following:

pen.CustomStartCap = new AdjustableArrowCap(10, 10, true);
pen.CustomEndCap = new AdjustableArrowCap(5, 5, true);

Don't forget: using System.Drawing.Drawing2D;

Re: Can't get Big Arrow on small Line

Anonymous9-Oct-05 9:33

Anonymous

9-Oct-05 9:33

it works thanks a lot!.

Application File Path

Golden Dragon9-Oct-05 5:08

Golden Dragon

9-Oct-05 5:08

Hi,

I am making a program and I need to get the path to the main application exe. How to do that the easies way? In Delphi there was a simple way, just reading the property PATH in the class APPLICATION. What is C# way for that?

Millan

Guffa9-Oct-05 5:20

Guffa

9-Oct-05 5:20

It's quite similar: Application.StartupPath.

---
b { font-weight: normal; }

Anoop Ananthan10-Oct-05 2:26

Anoop Ananthan

10-Oct-05 2:26

Use Environment.CurrentDirectory Property

Golden Dragon10-Oct-05 3:36

Golden Dragon

10-Oct-05 3:36

Yes, thanx. Stupid me. I used Application.StartupPath. Both works ok.