C# Discussion Boards - CodeProject

David Stone23-Aug-02 13:12

23-Aug-02 13:12

I have always coded the creation of objects directly into the event handlers. I think it would be fairly inefficient and complex to create a worker class that does that stuff for you. Smile | :)

David Stone

It seemed similar to someone saying, "Would you like to meet my knife collection?"
Ryan Johnston on Elaine's sig

Re: Windows Application Design Question

Chris Austin23-Aug-02 13:25

Chris Austin

23-Aug-02 13:25

Thanks for the reply David,

The real source of my anxiety comes from having quite a bit of stuff going on in the even handlers (object creation, method calls, and UI componet manipulation)and worring that perhaps I am not following what are considered the best practices.

Mabey I'll relax about a little Smile | :)

Thanks

Re: Windows Application Design Question

David Stone23-Aug-02 13:34

David Stone

23-Aug-02 13:34

Chris Austin wrote:
Mabey I'll relax about a little

I would. I've done tons of stuff on one button click before. Just remember to try not to interrupt the UI experience though. If you have so much stuff that the UI can't respond to any of the user's movements, then you might want to consider multithreading the app.

David Stone

But Clinton wasn't a predictable, boring, aging, lying, eloquent, maintainer-of-the-status-quo. He was a predictable, boring-but-trying-to-look-hip, aging-and-fat-but-seemingly-oblivious-to-it, lying-but-in-sadly-blatant-ways, not-eloquent-but-trying-to-make-up-for-it-by-talking-even-more, bringer-in-of-scary-and-potentially-dangerous-new-policies. And there was also Al Gore. It just wasn't *right*.

Shog⁹

Re: Windows Application Design Question

James T. Johnson24-Aug-02 7:47

James T. Johnson

24-Aug-02 7:47

May I point you to Joseph M. Newcomer's article "Optimization: Your Worst Enemy", in particular the 5 paragraph section titled "When not to optimize".

All of Joe Newcomer's articles deserve a read; but that one really opened my eyes.

James
"And we are all men; apart from the females." - Colin Davies

Re: Windows Application Design Question

bfarley26-Aug-02 4:20

bfarley

26-Aug-02 4:20

Interesting article. While I agree there is little point in optimizing for optimization's sake, the real opportunity here is code reuse. Separating your business logic from the interface makes it easier to reuse the code. One has to weigh the benefits against the added complexity

Bill F

ListBox selection

manson23-Aug-02 12:30

manson

23-Aug-02 12:30

and this is my third - last question guys ;]

i dont want the user to be able to change the selection, i only want the program to be able to change it

overriding OnSelectionChanged() or OnMouseDown() doesnt work

ps. i cant just disable the list box, because i dont want the colors
dimmed, and when you disable a control you dont have any influence on the colors it displays on the screen

manson

Re: ListBox selection

David Stone23-Aug-02 12:47

David Stone

23-Aug-02 12:47

myListBox.SelectionMode = System.Windows.Forms.SelectionMode.None;

Hope that helps. Smile | :)

David Stone

It seemed similar to someone saying, "Would you like to meet my knife collection?"
Ryan Johnston on Elaine's sig

Re: ListBox selection

manson23-Aug-02 12:50

manson

23-Aug-02 12:50

if you set selection mode to none, you CANNOT select any index in the listbox, even programmatically (you get an exception)

i cant do that, because i want the program to be able to select items in the list box

manson

Re: ListBox selection

Domenic Denicola23-Aug-02 17:05

Domenic Denicola

23-Aug-02 17:05

By default:

myListBox.SelectionMode = System.Windows.Forms.SelectionMode.None;

And then use this:

void SetListBoxText(int indexToSetTo)
{
   myListBox.SelectionMode = System.Windows.Forms.SelectionMode.One;
   myListBox.SelectedIndex = indexToSetTo;
   myListBox.SelectionMode = System.Windows.Forms.SelectionMode.None;
}

-Domenic Denicola- [CPUA 0x1337]
MadHamster Creations

"I was born human. But this was an accident of fate - a condition merely of time and place. I believe it's something we have the power to change..."

combining Brushes

manson23-Aug-02 12:26

manson

23-Aug-02 12:26

is it possible to combine two brushes (like use both on the same object on the screen), i.e. LinearGradientBrush and
HatchBrush and fill objects with them (i actually want to draw a
dashed-gradient line, so i do FillRectangle with height=1)

or do I have to crate my own brush class derived from
System.Drawing.Brush?

manson

Re: combining Brushes

David Stone23-Aug-02 12:28

David Stone

23-Aug-02 12:28

I believe that the Brush type is an enum and that it does have the [Flags] attribute. So you could say:

myDrawingObject.BrushType = Brush.LinearGradientBrush | Brush.HatchBrush

Hope that works. Smile | :)

David Stone

It seemed similar to someone saying, "Would you like to meet my knife collection?"
Ryan Johnston on Elaine's sig

Re: combining Brushes

manson23-Aug-02 12:48

manson

23-Aug-02 12:48

ee.. were talking c# here

theres no such thing as Brush.LinearGradientBrush, cos Brush is an abstract class, which is extended by LinearGradientBrush and HatchBrush (which, by the way, are not enums unfortuantely, and cannot be treated with OR operator '|')

and above all, what is BrushType?? no such member in the whole .NET class library either

tell me you were just joking

manson

Re: combining Brushes

David Stone23-Aug-02 13:08

David Stone

23-Aug-02 13:08

I wasn't sure if there was a property that was BrushType or not. Sorry about that. I didn't look to confirm. I was thinking about the Brushes class and it's read only properties. But those are for colors. Blush | :O

Let's start over. What are you trying to draw?

David Stone

It seemed similar to someone saying, "Would you like to meet my knife collection?"
Ryan Johnston on Elaine's sig

MinimumSize - what is that for?

manson23-Aug-02 12:19

manson

23-Aug-02 12:19

setting MinimumSize for an MdiChild Form does nothing, you can still resize the Form to a smaller size than MinimumSize

checking if the Form has been resized to a smaller size than MinimumSize
(and resizing it back) in the Resize event handler seems the only
solution so far, but it doesnt look good in the runtime of course..

what am i missing?

ps. MaximumSize and MinimumSize do work for MdiParents and non-Mdi Forms, but
they dont work for MdiChildren

at least it looks like it

is there any way around it?

manson

Enums

Nnamdi Onyeyiri23-Aug-02 11:14

Nnamdi Onyeyiri

23-Aug-02 11:14

How do i make an enum, such that when you are assigning a property of that enum, you can specify more that one of the flags, e.g.

someThing.Proprty = AnEnum.Foo | AnEnum.Bar;

and is there something special i have to do to find which ones were specified?

Suspicious | :suss: Email: theeclypse@hotmail.com URL: http://www.onyeyiri.co.uk
"All programmers are playwrights and all computers are lousy actors."

Re: Enums

Michael Mac23-Aug-02 11:47

Michael Mac

23-Aug-02 11:47

Use FlagsAttribute
Here is an example:

[Flags]
public enum AA
{
   ...
}

43 68 65 65 72 73 2c
4d 69 63 68 61 65 6c

Re: Enums

leppie24-Aug-02 2:58

leppie

24-Aug-02 2:58

Nnamdi Onyeyiri wrote:
and is there something special i have to do to find which ones were specified?

Yes, unfortunately Frown | :(

1. Flags Enums must be bit settable ie

enum MyEnum {
  None  = 0x00, //not necessary , but handy, u could always pass 0.
  FlagA = 0x01,
  FlagB = 0x02,
  FlagC = 0x04,
  FlagD = 0x08,
  FlagE = 0x10,
  FlagF = 0x20,
  FlagG = 0x40,
  FlagH = 0x80
}

2. To get the value (this is my difficult part as bit operations is somethin my mind cant process yet). I use this snippet to view Flags.

public static string PrintFlags(object enumvalue)
{
  Type t = enumvalue.GetType();
  string output = "";
  foreach(string enumName in (string[])Enum.GetNames(t)) 
  {
    // We add the enum name, but only if it is selected.
    if ((((int)enumvalue) & (int)Enum.Parse(t, enumName)) != 0) 
      output += "[" + enumName + "]";
  }
  return output;
}

To get value is something like (from above):

if ((enumvalue & MyEnum.FlagA) != 0) then flag is set, else not set

Hope this helps Smile | :)

I think I have learnt something at least Smile | :)

MYrc : A .NET IRC client with C# Plugin Capabilities. See
http://sourceforge.net/projects/myrc for more info. Big Grin | :-D

Re: Enums

Nnamdi Onyeyiri24-Aug-02 3:03

Nnamdi Onyeyiri

24-Aug-02 3:03

JTJ said i can do this

[Flags]
enum Stuff {
itemA = 1,
itemB = 2,
itemC = 4
}

then to get the ones set, do this

Stuff myStuff = Stuff.itemA | Stuff.itemB;
....
bool hasItemA = (myStuff & Stuff.itemA) == Stuff.itemA;

Suspicious | :suss: Email: theeclypse@hotmail.com URL: http://www.onyeyiri.co.uk
"All programmers are playwrights and all computers are lousy actors."

Re: Enums

leppie24-Aug-02 3:24

leppie

24-Aug-02 3:24

The 1st part I did like that to show the bit formation Smile | :)

Re, the getting part, thats where my math is &^%&^% with my head.

I cant see how :

bool hasItemA = (myStuff & Stuff.itemA) == Stuff.itemA; //JTJ version
bool hasItemA = (myStuff & Stuff.itemA) != 0; //My (copied) version

can be the same ??? Confused | :confused:

To me , mine looks correct, I could be wrong.

MYrc : A .NET IRC client with C# Plugin Capabilities. See
http://sourceforge.net/projects/myrc for more info. Big Grin | :-D

Re: Enums

Paul Ingles25-Aug-02 7:29

Paul Ingles

25-Aug-02 7:29

& is a bitwise and operator, and works something like this (I'm sure I'll be jumped on if I'm wrong here Smile | :)

Ok, assuming that the myStuff variable contains the bit flags, and exists as:

01001001

Now, assuming that Stuff.itemA is set to 00000001 then performing an AND bitwise operator on the two should yield the following

01001001 +
00000001
---------
00000001

The result will only be 1 where both the parameters are 1, so 1+1=1, 0+1=0, 0+0=0 etc.

Consequently the result ought to be itemA again. As a result, both yours and JTJ's version ought to be correct, since they'll both return a result != 0.

--
Paul
"I need the secure packaging of Jockeys. My boys need a house!"
- Kramer, in "The Chinese Woman" episode of Seinfeld

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Re: Enums

leppie25-Aug-02 7:48

leppie

25-Aug-02 7:48

Thanx Paul, nice explanation. I will look at it a bit more to remember it Smile | :)

MYrc : A .NET IRC client with C# Plugin Capabilities. See
http://sourceforge.net/projects/myrc for more info. Big Grin | :-D

help

imran_rafique23-Aug-02 9:30

imran_rafique

23-Aug-02 9:30

i want to move mouse curser programatically and want to get any key pressed how to do that in csharp like the hooks in vc++ ?

r00d0034@yahoo.com

Re: help

David Stone23-Aug-02 10:02

David Stone

23-Aug-02 10:02

I know that the keystroke program can be done:

http://www.c-sharpcorner.com/Code/2002/July/LeyLoggerApp.asp[^]

However, I don't know about moving the mouse. Sorry about that. Hope the keystroke thing was of some help.

David Stone

It seemed similar to someone saying, "Would you like to meet my knife collection?"
Ryan Johnston on Elaine's sig

is it possible ?

imran_rafique23-Aug-02 9:22

imran_rafique

23-Aug-02 9:22

is it possible to call any MFC Dialog in csharp code if yes plz tell how ?

r00d0034@yahoo.com

Re: is it possible ?

David Stone23-Aug-02 10:05

David Stone

23-Aug-02 10:05

Why not just design your own? VS.NET has a cool dialog editor as part of the resource editor.

David Stone

It seemed similar to someone saying, "Would you like to meet my knife collection?"
Ryan Johnston on Elaine's sig

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