Re: if statement - C# Discussion Boards

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Re: Is this a bug in .NET 2.0?

adfgh752-Nov-06 3:54

adfgh75

2-Nov-06 3:54

Well yes, I have set KeyPreview to true on the form (and breakpoints to trace the event)and it still doesn't throw any KeyDown event when when I press the arrow keys, but it throws it when I press any other key. If I let the class inherit from Panel instead of UserControl or Control it works perfect.

However I've discovered that if I override the ProcessCmdKey() function in the form and process the key pressed there instead it will work.

.NET

if statement

fmardani2-Nov-06 1:57

fmardani

2-Nov-06 1:57

Hi,
Can you please let me know what is wrong with the following if statement?
I believe the following values should make the statement to show the messagebox.
Do you agree?
Thanks

intPosHomeUS= -1
intPosHostUS= 7
intPosHomeUK= 7
intPosHostUK= -1

if (!(intPosHomeUS > 0 && intPosHomeUK > 0) || (intPosHomeUK > 0 && intPosHostUS > 0))
{
//show messagebox...
}
else
{
//print report...
}

Re: if statement

sam#2-Nov-06 2:16

sam#

2-Nov-06 2:16

no problem it should work fine

Re: if statement

J4amieC2-Nov-06 2:20

J4amieC

2-Nov-06 2:20

firstly I think youve made a typo (either in your code or in transposing it to a post)

fmardani wrote:
if (!(intPosHomeUS > 0 && intPosHomeUK > 0) || (intPosHomeUK > 0 && intPosHostUS > 0))

should that be

if (!(intPosHomeUS > 0 && intPosHomeUK > 0) || (intPosHostUK > 0 && intPosHostUS > 0))

if not, and its correct, I could break down the code as

if(! (false && true) || (true && true))

breaks down further as

if( ! (false || true) )

and once more as

if(!true)

so

!true == false

so your message box will not show.

---

How to get answers to your questions[^]

Re: if statement

eggsovereasy2-Nov-06 3:30

eggsovereasy

2-Nov-06 3:30

Doesn't it evaluate to:

(!false || true)

rather than

!(false || true)

Which would of course trigger the message box? I tend to go overboard with the parens just to make sure I'm negating the right thing because of stuff like this.

Re: if statement

J4amieC2-Nov-06 3:39

J4amieC

2-Nov-06 3:39

eggsovereasy wrote:
I tend to go overboard with the parens just to make sure I'm negating the right thing because of stuff like this.

me too!

In my post I am assuming (rather than have tested) that it is evaluated as

!(false || true)

rather than

(!false || true)

---

How to get answers to your questions[^]

Re: if statement

Andrew Rissing2-Nov-06 3:43

Andrew Rissing

2-Nov-06 3:43

The negation operator (!) has a higher precedence than the logical or operator. I think you made a typo yourself when you went from steps:

if(! (false && true) || (true && true))

To:

if( ! (false || true) )

Personally, I would suggest just using the debugger and putting a watch in to see what exactly is going in. Put the full statement "(!(intPosHomeUS > 0 && intPosHomeUK > 0) || (intPosHostUK > 0 && intPosHostUS > 0))" and then break it down into pieces to find the error.

As a side note, I'm not a big fan of putting a negation like that because it always seems to trip me up (may just be me). So, I typically pass the negation through the set...so you'd have something like this instead:

if (intPosHomeUS <= 0 || intPosHomeUK <= 0 || (intPosHostUK > 0 && intPosHostUS > 0))

It's just DeMorgan's Law...you can find more about it here[^].

Re: if statement

Dan Neely2-Nov-06 4:11

Dan Neely

2-Nov-06 4:11

Andrew Rissing wrote:

As a side note, I'm not a big fan of putting a negation like that because it always seems to trip me up (may just be me). So, I typically pass the negation through the set...so you'd have something like this instead:

It tends to trip me up as well, but I prefer writing the exression in the intuitive 'as english' format and either using a temp var for the base expression and then notting the temp in the expression or switching the then and else clauses around to avoid the negation all together.

--

Rules of thumb should not be taken for the whole hand.

Re: if statement

Guffa2-Nov-06 4:37

Guffa

2-Nov-06 4:37

fmardani wrote:
I believe the following values should make the statement to show the messagebox.

Yes, it should, and it does.

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

Re: if statement

ed^nrgc2-Nov-06 6:23

ed^nrgc

2-Nov-06 6:23

Is this a logic issue? I noticed that you're not checking for a value from intPosHostUK

Keys shortcuts problem

Tavbi2-Nov-06 1:19

Tavbi

2-Nov-06 1:19

Hi,

I need to know how can I create shotcut to myButton on form when I press key F10 independent of current active control on form, without using "ShortcutKey" in "ToolStipMenuItem".

I can do this if myButton is active control on form. I explicitly need to use key F10, so I can't use an & (ampersand) in a button text.

Thanks for help

Re: Keys shortcuts problem

luckykhalid2-Nov-06 1:29

luckykhalid

2-Nov-06 1:29

handle key down or key up event of the form and then trigger click event by;
if(e.KeyCode == Keys.F10)
button1.PerformClick();

hope it helps.

Regards
Khalid

Re: Keys shortcuts problem

Martin#2-Nov-06 1:31

Martin#

2-Nov-06 1:31

Hello,

And dont't forget to set:

this.KeyPreview = true;

All the best,

Martin

Re: Keys shortcuts problem

Tavbi3-Nov-06 1:21

Tavbi

3-Nov-06 1:21

Thanks both, it really works.

Re: Keys shortcuts problem

Tavbi3-Nov-06 1:28

Tavbi

3-Nov-06 1:28

Hi,

I have just one more question. Can I check if ALT+F1 pressed?

Thanks,

Jure

Re: Keys shortcuts problem

Martin#7-Nov-06 1:32

Martin#

7-Nov-06 1:32

Hello,

Yes you can!

if (e.Alt && e.KeyCode == Keys.F1)

Hope it's not too late, but I didn't got your post.

All the best,

Martin

Re: Keys shortcuts problem

Tavbi8-Nov-06 4:15

Tavbi

8-Nov-06 4:15

Thanks, it's not too late.

Thanks again,
Jure

Linq - Problems with conversion [modified]

Storme2-Nov-06 1:05

Storme

2-Nov-06 1:05

Excuse me for being brief, but it is self explanatory.

So I make a query with linQ, and then try to make a 2nd query on the previous results, but there i get an error.

            List<clsHotel> q = from d in dbGet.Hotels()  // dbGet.Hotels() returns List<clsHotel><br />
                    select d;<br />
<br />
            if (chkHalfpension.Checked) {<br />
                List<clsHotel> z = from x in q     // Error occures here on q<br />
                                            where x.Naam == "Bon jour"   <br />
                                            select x;<br />
            }

It returns the following error on that line:

Error 1 Cannot implicitly convert type 'System.Collections.Generic.IEnumerable<hotelmanager.data.clshotel>' to 'System.Collections.Generic.List<hotelmanager.data.clshotel>'. An explicit conversion exists (are you missing a cast?)

If anyone could please help.

Thanks in advance !

-- Edit --

The weird thing is:

This code also doesnt works:

List<clsHotel> q = from d in dbGet.Hotels()  // dbGet.Hotels() returns List<clsHotel><br />
                    select d;<br />
<br />
                List<clsHotel> z = from vx in dbGet.Hotels()   // also gives error here<br />
                                   select vx;

It throws the same error, but the code is the same :s
Guess it's an bug in c#3.0 ?

-- modified at 8:18 Thursday 2nd November, 2006

Re: Linq - Problems with conversion

ed^nrgc2-Nov-06 6:27

ed^nrgc

2-Nov-06 6:27

instead of list, have you tried var?

Re: Linq - Problems with conversion

Storme2-Nov-06 6:52

Storme

2-Nov-06 6:52

Yes, keeps saying the same error.

I guess you can't do 2 of that select things in the same function, wich is to bad Frown | :(

Re: Linq - Problems with conversion

ed^nrgc2-Nov-06 6:55

ed^nrgc

2-Nov-06 6:55

Have you tried IEnumerable < string > < == remove spaces

Re: Linq - Problems with conversion

Storme2-Nov-06 7:05

Storme

2-Nov-06 7:05

This works ! (except i used clsHotel class, not string)

Thanks alot edboe ! Big Grin | :-D

Re: Linq - Problems with conversion

ed^nrgc2-Nov-06 6:59

ed^nrgc

2-Nov-06 6:59

Another option would be to create each search in a separate function/method.

Changing a Color on the fly

Gareth H2-Nov-06 0:53

Gareth H

2-Nov-06 0:53

What i want to be able to do is change a Color that i get from a method to a lighter version. E.g: If its red, make it a lighter shade of red.

Any ideas how i'd do this?

Regards,
Gareth.

Re: Changing a Color on the fly

Martin#2-Nov-06 1:06

Martin#

2-Nov-06 1:06

Hello,

I think this should do it.

Color _lightcolor = ControlPaint.Light(Color.Red);

Hope that helped you.

All the best,

Martin

Last Visit: 31-Dec-99 18:00 Last Update: 25-May-24 13:43

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