C# Discussion Boards - CodeProject

19-Jul-09 20:55

Unrelated: What's with the @ in @label3? It seems unnecessary.

left pane

Satish Pai19-Jul-09 18:53

Satish Pai

19-Jul-09 18:53

Hi Experts,

Can anybody tell me how can i add left pane in Windows. The left pane should be my usercontrol.

You can take this example http://i.d.com.com/i/dl/media/dlimage/14/91/06/149106_large.jpeg[^]

Mycroft Holmes19-Jul-09 20:17

Mycroft Holmes

19-Jul-09 20:17

I presume you mean in Winforms.

DOCK is the property you are looking for. Your user control will have a dock property.

User the Z order (bring to front/ send to back) of the control to manage the positioning in the control hierarchy.

Never underestimate the power of human stupidity
RAH

Satish Pai19-Jul-09 21:03

Satish Pai

19-Jul-09 21:03

No i am talking abt Window, Like if u open a Drive it should have Left pane Just has same in M-Files.

Ashfield19-Jul-09 21:40

Ashfield

19-Jul-09 21:40

Which is what Mycroft was also talking about. You need to write the code to do what you need, it isn't magic.

Bob
Ashfield Consultants Ltd
Proud to be a 2009 Code Project MVP

Cubic roots of negative numbers, Math.Pow()

OriginalGriff19-Jul-09 21:50

OriginalGriff

19-Jul-09 21:50

I think you mean that you want the form divided into two panels, a left pane and a right pane? If so, then look at SplitContainer control, which does exactly that.

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Wizard

john563219-Jul-09 18:42

john5632

19-Jul-09 18:42

Hi All,

I am new to c#, I have a requirement to design a wizard in c# So please guide to do this.

Re: Wizard

N a v a n e e t h19-Jul-09 20:10

N a v a n e e t h

19-Jul-09 20:10

There are many here at CP. Have you searched? Here are few

1 - Designer centric Wizard control[^]

2 - A .NET Wizard control[^]

Smile | :)

Navaneeth

How to use google | Ask smart questions

Re: Wizard

john563219-Jul-09 23:21

john5632

19-Jul-09 23:21

Thank you but I want to create my own, don
t want to use of others control.

Please let me know how to do that?

Brandon Walton19-Jul-09 17:22

19-Jul-09 17:22

Hello everyone,

I ran into a bit of an issue with Math.Pow() today while doing some work with cubic equations. The cubic root of a real negative number, is a real negative number, correct? For some reason, when X is a negative value, Math.Pow(X, (double)1/3) returns NaN instead of a negative real number.

Hopefully I'm not forgetting something...

Any help would be appreciated, thanks.

PIEBALDconsult19-Jul-09 17:28

19-Jul-09 17:28

Huh, must not realize what you're trying to do. Maybe write your own?

The Algorithm (and Mathematics) forum may be a better place to post this.

Brandon Walton19-Jul-09 17:42

19-Jul-09 17:42

Opps, sorry if I posted in the wrong forum, it just seemed like a C# thing.

In case you didn't know, a cubic root is just like a square root (x^(1/2)). As in 2^3 = 8, 8^(1/3) = 2.

PIEBALDconsult19-Jul-09 17:53

19-Jul-09 17:53

Not the worst choice of forum.

I realize that about power and root, on the other hand, a double can't represent 1/3 precisely.

Brandon Walton19-Jul-09 18:36

19-Jul-09 18:36

It gives the correct answer if X is positive in Math.Pow(X, (double)1/3), so something weird is going on...

harold aptroot19-Jul-09 17:53

harold aptroot

19-Jul-09 17:53

Interesting problem here. Math.Pow probably (I'm not sure, but it's what I would do) uses Taylor series to calculate e^(x * ln(y)) (where ^ denotes exponentiation, and the goal is pow(x,y))
And the natural logarithm of a negative real is of course a complex, which it might not be able to handle, causing a NaN somewhere which then propagates through all further calculations to end up in the result.

This is just a theory, and I wouldn't bet anything on it, but I think it's plausible.

Brandon Walton19-Jul-09 18:22

19-Jul-09 18:22

Yeah, that sounds right. NaN seems to be the C# default for anything that would be complex.

I made a little work around which seems to work.

static public double Pow(double x, double y)
{
    return y < 1 && (1 / y) % 2 == 1 && x < 0 ? -Math.Pow(Math.Abs(x), y) : Math.Pow(x, y);
}

Though this seems really improper...

harold aptroot19-Jul-09 18:43

harold aptroot

19-Jul-09 18:43

Brandon Walton wrote:
(1 / y) % 2 == 1

This looks dangerous, equality of doubles.. well.. you've heard that before. Are you sure it's not "!= 0"?

But anyway, the default math library that comes with .NET doesn't do complex math. It's a shame, but that's how it is.. Now, I know you probably meant it the right way, so no offense, but just in case (and for completeness) : normal CPU's implement the IEEE 754 kind of math so NaNs just happen, C# can't help it (ok it could, but that would just make it terribly slow at floating point math)

Brandon Walton19-Jul-09 19:09

19-Jul-09 19:09

Ohh, I always assumed NaN were native to C#. I need to get out more...

harold aptroot wrote:
This looks dangerous, equality of doubles

Just the way I like it Cool | :cool:

. But yeah, just pretend you didn't see that.

harold aptroot wrote:
Are you sure it's not "!= 0"?

And yeah, should be != 0 Dead | X|

PIEBALDconsult19-Jul-09 18:53

19-Jul-09 18:53

I would try it normally first, then only do weird stuff if the result is NaN (or on Exception).

harold aptroot19-Jul-09 18:59

harold aptroot

19-Jul-09 18:59

Math.Pow([value smaller than 0], [non integral value]) is always NaN, according to the specs[^]
What else do you suggest?

I may be reading it wrong (nearly 7 in the morning, so I make mistakes easily), but to me it looks like you're suggesting that he do what he did already - which already proved to go wrong..

PIEBALDconsult19-Jul-09 20:48

19-Jul-09 20:48

But if it's to be a general-use routine, why not assume it will be used in the normal way and only try to add special handling as a backup?

How many times each unique String appears in the collection.

Luc Pattyn20-Jul-09 1:05

Luc Pattyn

20-Jul-09 1:05

to summarize what others have said:

1. read the doc, it lists special cases including yours:
x < 0 but not NegativeInfinity; y is not an integer, NegativeInfinity, or PositiveInfinity ==> NaN

2. realize Math.Pow is using exp(y*ln(x)) so x better be positive
(you don't have to know that, but it justifies some of the documented special cases)

3. realize (double)1/3 can't be stored exactly in binary (not really relevant here)

4. make your own cubicroot method, which performs sign(x)*Math.Pow(abs(x),y)

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

The quality and detail of your question reflects on the effectiveness of the help you are likely to get.
Show formatted code inside PRE tags, and give clear symptoms when describing a problem.

dsrao19-Jul-09 17:14

dsrao

19-Jul-09 17:14

Hi All,

Here are the code...

//

List< String >category=new List < String >();

category.Add("House");
category.Add("Car");
category.Add("Dog");
category.Add("Car");

I want to show report like this...

Name Count
===== =====
Car 2
Dog 1
House 1

Please let me know how to do the above output.

Thanks & Regards
Rao

Re: How many times each unique String appears in the collection.

PIEBALDconsult19-Jul-09 17:16