if statement - C# Discussion Boards

Re: simple grafics problem

V.2-Nov-06 3:09

2-Nov-06 3:09

Start your application, take a marker and set a dot on the screen...

Seriously though: look into the Graphics[^] class

V.

Stop smoking so you can: Enjoy longer the money you save.
Moviereview Archive

Re: simple grafics problem

J4amieC2-Nov-06 3:45

J4amieC

2-Nov-06 3:45

Pretty easy.

1) Override the OnPaint method of your form.

2) This method gives access to PaintEventArgs which has a property named Graphics which you will use

3) You cant draw a point, but you can draw a rectangle with dimentions 1,1 - ie one pixel square at your given point (note the point will be the top right corner of your rectangle.

some code to get you started (untested, typed quickly)

using System.Drawing;

public override void OnPaint(PaintEventArgs e)
{
  Point myPoint = new Point(20,20);
  Graphiocs g = e.Graphics;
  using(SolidBrush brush = new SolidBrusgh(Color.Black))
  {
    g.FillRectangle(brush,new Rectangle(myPoint, new Size(1,1) ));
  }
}

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Re: simple grafics problem

rzvme2-Nov-06 20:50

rzvme

2-Nov-06 20:50

thanks guys

rzvme

Is this a bug in .NET 2.0?

adfgh752-Nov-06 2:02

adfgh75

2-Nov-06 2:02

I'm developing an windows application in .NET 2.0 where the user is supposed to navigate around the application using the arrow keys(I'm using KeyDown event to handle user key input).

My problem is that I want to use UserControls in my application but whenever I add my UserControls to my windows form the form don't recieve any KeyDown events when I press the arrows keys, however it reacts to any other keys being pressed!

Is this a bug and is there another way to do this?

Thanks

Vester

Re: Is this a bug in .NET 2.0?

sam#2-Nov-06 2:35

sam#

2-Nov-06 2:35

there is no such . you must be unable to handle event properly.elaborate more about your control's desired behaviour and what do you want

Re: Is this a bug in .NET 2.0?

Michael P Butler2-Nov-06 2:53

Michael P Butler

2-Nov-06 2:53

adfgh75 wrote:

My problem is that I want to use UserControls in my application but whenever I add my UserControls to my windows form the form don't recieve any KeyDown events when I press the arrows keys, however it reacts to any other keys being pressed!

The key press is probably being handled by another control. Have you tried setting KeyPreview[^]to true

Michael

CP Blog [^] Development Blog [^]

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.

---

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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?

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