C# Discussion Boards - CodeProject

BlitzPackage18-Jun-07 5:44

18-Jun-07 5:44

Good People,

In C++ when I want to overload the addition operator ('+') I can return a reference to the object calling that function in order to enable a series of ensuing mathematical operations (i.e. YourObject = MyObject + ThisObject + ThatObject). However, in C#, if I'm correct, you cannot return a reference to an object. So, what's the best way to overload the addition operator to enable ensuing mathematical operations such as the one described above.

Any help or guidance you can provide would be greatly appreciated.

Thank you.

BP

Re: C# Overloading

PIEBALDconsult18-Jun-07 6:01

PIEBALDconsult

18-Jun-07 6:01

BlitzPackage wrote:
you cannot return a reference to an object

Well of course you can, but operators in C# are static, so

BlitzPackage wrote:
I can return a reference to the object calling that function

doesn't apply (an ~~object~~ instance isn't calling the function).

I don't write operators very often, but I just took a look at one place I do (my Rational class):

public static Rational
operator +
(
    Rational Op1
,
    Rational Op2
)
{
    decimal lcm = PIEBALD.Lib.LibMth.LCM ( Op1.denominator , Op2.denominator ) ;

    return ( new Rational
    (
        ( lcm / Op1.denominator * Op1.numerator ) + ( lcm / Op2.denominator * Op2.numerator )
    ,
        lcm
    ) ) ;
}

This code instantiates a new Rational and sets its value to the sum of the two operands, then returns a reference to that instance.

Re: C# Overloading

led mike18-Jun-07 6:36

led mike

18-Jun-07 6:36

BlitzPackage wrote:
in order to enable a series of ensuing mathematical operations (i.e. YourObject = MyObject + ThisObject + ThatObject).

Yes as PIEBALDconsult pointed out. However unless all those objects are the same type you will need overloads including those types.

Alternatively, what I found to be more helpful with multiple classes was to create the binary overloads using underlying intrinsic type for the right hand side, supply the explicit type operator and then include casts to the intrinsic type in your math statement.

Validating TextBox

t4ure4n18-Jun-07 4:37

t4ure4n

18-Jun-07 4:37

I have two text boxes which i want to validate

First TextBox:
Only Allow an integer as input, Check If it is not then make it an integer and put out a warning msgbox that it has been changed.

Second TextBox:
Only Allow allow a decimal number (with 1 decimal point only).
So if it is has two decimal places then trim it down to one and put out a warning.

Hope I have made my self clear

o O º(`'·.,(`'·., ☆,.·''),.·'')º O o°
»·'"`»* *☆ t4ure4n ☆* *«·'"`«
°o O º(,.·''(,.·'' ☆`'·.,)`'·.,)º O o°

Re: Validating TextBox

Fatbuddha 118-Jun-07 4:57

Fatbuddha 1

18-Jun-07 4:57

on the first you can write something like that:
try{
int.Pars(TextBox.Text);
catch(){
//if it is not a number
}

On the other you can make the same and than check if the Number div 10 == 0;
Then you should have just one decimal point.

I hope that works, don´t know the exceptoion Type that is thrown if its not a number

Cheers

You have the thought that modern physics just relay on assumptions, that somehow depends on a smile of a cat, which isn’t there.( Albert Einstein)

Re: Validating TextBox

DavidNohejl18-Jun-07 5:06

DavidNohejl

18-Jun-07 5:06

Fatbuddha 1 wrote:
try{
int.Pars(TextBox.Text);
catch(){
//if it is not a number
}

There is int.TryParse() for this scenario.

Fatbuddha 1 wrote:
don´t know the exceptoion Type that is thrown if its not a number

FormatException

"Throughout human history, we have been dependent on machines to survive. Fate, it seems, is not without a sense of irony. " - Morpheus
"Real men use mspaint for writing code and notepad for designing graphics." - Anna-Jayne Metcalfe

Re: Validating TextBox

Martin#18-Jun-07 5:10

Martin#

18-Jun-07 5:10

dnh wrote:
There is int.TryParse() for this scenario.

Only in .Net>1.1
But in this case I would use double.TryParse, with System.Globalization.NumberStyles.Integer as param.

Re: Validating TextBox

DavidNohejl18-Jun-07 5:14

DavidNohejl

18-Jun-07 5:14

True, OP doesn't specify which version of framework he uses. If it is 1.x then indeed your approarch seems to be best Smile | :)

Re: Validating TextBox

Martin#18-Jun-07 5:22

Martin#

18-Jun-07 5:22

Thank you!
Smile | :)

Re: Validating TextBox

Fatbuddha 118-Jun-07 21:14

Fatbuddha 1

18-Jun-07 21:14

Sorry for tha. I just came for a month from Java programming to C#. Smile | :)

Cheers

You have the thought that modern physics just relay on assumptions, that somehow depends on a smile of a cat, which isn’t there.( Albert Einstein)

Re: Validating TextBox

lsconyer18-Jun-07 4:57

lsconyer

18-Jun-07 4:57

I hope this helps...

private void textBox1_KeyUp(object sender, KeyEventArgs e)
{
try
{
int intValue = int.Parse(textBox1.Text);
}
catch (FormatException)
{
MessageBox.Show(textBox1.Text + " is not an integer");
}
}

private void textBox2_KeyUp(object sender, KeyEventArgs e)
{
try
{
decimal decValue = decimal.Parse(textBox2.Text);

string dec = decValue.ToString();

int i = dec.IndexOf(".");

if (dec.Length > (i + 1))
{
dec = dec.Substring(0, (i + 2));
throw new Exception("You value of " + textBox2.Text + " has too many numbers following the decimal point. You're new value is " + dec);
decValue = decimal.Parse(dec);
textBox2.Text = dec;
}
}
catch (FormatException)
{
MessageBox.Show(textBox1.Text + " is not an integer");
}
}

Lester
http://www.lestersconyers.com

Re: Validating TextBox

DavidNohejl18-Jun-07 5:11

DavidNohejl

18-Jun-07 5:11

If it is WinForms, use MaskedTextBox[^], if it is ASP.NET web app, use RegularExpressionValidator [^] or maybe RangeValidator[^].

Simple code generation

gantww18-Jun-07 4:03

gantww

18-Jun-07 4:03

Hello all,
Does anyone know of an application that can take an XML file and generate a class structure for reading and writing it? I just need something very simple, just to get started.

Re: Simple code generation

Giorgi Dalakishvili18-Jun-07 4:07

Giorgi Dalakishvili

18-Jun-07 4:07

I'm not sure but this might help you:
XML Schema Definition Tool (Xsd.exe)[^]

#region signature
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#endregion

Re: Simple code generation

gantww18-Jun-07 4:36

gantww

18-Jun-07 4:36

I did find this. Hopefully it will do what I need:

http://marcclifton.com/tabid/93/Default.aspx

Graphics.DrawLines and Coordinate translation

Jon Hulatt18-Jun-07 3:37

Jon Hulatt

18-Jun-07 3:37

Hi All,

One section of my app involves drawing multi point lines over the top of an image. The image scrolls.

I have internally a list of (world) coordinates, and in every OnPaint handler i'm recalculating the screen coordinates that these correspond to, so that I have a Point[] array, which can be used in Graphics.DrawLines

Problem is that the coordinate calculations are rather slow, and profiling the code shows quite a chunk of time wasted in this part of the app.

I can precalculate the coordinates, but they will still need translating as the image is drawn because it scrolls. But this translation would be simple, because it's just linear.

Does anyone know of an optimised way of translating a large set of coordinates? Or will i just need to loop around my list and do it that way?

Thanks

Jon

using System.Beer;

Re: Graphics.DrawLines and Coordinate translation

Luc Pattyn18-Jun-07 3:49

Luc Pattyn

18-Jun-07 3:49

Hi Jon,

the easiest approach would be to rely on Graphics.TranslateTransform(); this will
cause the calculations to occur everytime OnPaint runs, but they will happen in the
most optimized way Microsoft has implemented in Graphics.

One way to speed up things even more is to somehow avoid painting stuff that will
be clipped away due to the scrolling; this requires you keeping all your stuff
in an ordered fashion so you can skip those parts that fall definitely above
the currently visible part, as well as those parts that definitely fall below it.
Of course these decisions could be based on world coordinates.

Depending on the dynamics of your app, you may also consider drawing the image
and all the lines once in an off-screen buffer (Bitmap), and show only the
relevant parts as needed.

Hope this helps.

Smile | :)

Luc Pattyn

[My Articles] [Forum Guidelines]

Re: Graphics.DrawLines and Coordinate translation

Jon Hulatt18-Jun-07 4:00

Jon Hulatt

18-Jun-07 4:00

Hi Luc,

Thanks for the comments.

TranslateTransform looks like it's going to be really helpful, I shall experiment and see if it makes some performance gains.

I already only draw approximately what is needed. I simplified a little in my post - the image is actually a grid of image tiles, which are usually in the region of 150px by 150px. Each image tile has it's own list of coordinates which are on top of it, which are calculated at the start. I have logic to tell which tiles are in view in any given OnPaint call, so I only do extra line drawing where a tile is clipped by the edge of the window.

Thanks

Jon

using System.Beer;

Verfying Chain Verification Process

suprajav18-Jun-07 3:29

suprajav

18-Jun-07 3:29

Hi Friends,

I am using asp.net with c#.I am new to Chain Verification Process.i need to verify client certificate with root certificate of the server .in that i was struck with verifing the publickey.i am able to dispaly the Thumbprint and publickey of the certificates but i am unable to verify that Thumbprint and publickey.
It is greatful to give an example which is help to me

Cheers,
Happy Coding

SharePoint Development

alexfromto18-Jun-07 3:09

alexfromto

18-Jun-07 3:09

Hello everyone.

I’m .NET developer (VB.NET). At the company I work I use VS 2003 and .NET Framework 1.1 to develop different tools (web based and windows based) to replace some of the process in my company, basically make some tasks easy to do.

My company is evaluating SharePoint Server 2007 (MOSS) to get us company Intranet and of course use document management and other collaboration tools that SharePoint has to offer. Of course I will be programming in C# and that’s why I’m in the middle of adapting to the new language.

Did anyone have any experience with SharePoint development and/or customization? I would like to get any information as I can get: links to the sites, books, etc. Basically anything that can help me to get started. Please consider me as new user and I know nothing about it. Where do I start (especially development for SharePoint)?

I found the following books at Amazon.com. Do you think these would be enough or I will need anything else?

http://www.amazon.ca/Professional-SharePoint-2007-Development-Holliday/dp/0470117567/ref=pd_sim_b_3/701-8834183-4638738?ie=UTF8&qid=1181779059&sr=8-1
http://www.amazon.ca/Beginning-SharePoint-2007-Building-Solutions/dp/0470124490/ref=pd_sim_b_3/702-7805079-5962455?ie=UTF8&qid=1181779059&sr=8-1

Thank you very much for your help.

Movable Selection Box

R.Myers18-Jun-07 2:54

R.Myers

18-Jun-07 2:54

I have a program where i need to display an image in a picturebox & have users be able to select a part of the image for printing. I haven't be able to find any method of accomplishing this. I've tried drawing a rectangle on the image but drawing and re-drawing the image take far too long (these are very large images).
Any ideas/links?
Thanks

R.Myers

Re: Movable Selection Box

Chintan.Desai18-Jun-07 3:22

Chintan.Desai

18-Jun-07 3:22

It is obvious to use rectangle to allow user to draw from source x,y coordinate to destination x,y coord. BitBlt()(Bitmap Block Transfer) available in VC would help to do ur task easily.

Wink | ;)

Regards
Chintan
www.visharadsoft.com
(Nothing is so purify as KNOWLEDGE)

Re: Movable Selection Box

R.Myers18-Jun-07 7:35

R.Myers

18-Jun-07 7:35

Thanks for the response. Do you (or anyone else) know of a newbie-type guide to using BitBlt? I've been looking, but i haven't found anything.
Thanks again

R.Myers

ListView control and key strokes

zaboboa18-Jun-07 2:15

zaboboa

18-Jun-07 2:15

Hello,

If the listview control is populated with items, and user preses for example key "r", the list view control scrolls to the first object in the listview control whose text starts with letter "r". How can I achive this programatically? Meaning, if I have a button, and when user presses the button, it sends a key stroke event to listview control with letter "r".

Thank you.

Re: ListView control and key strokes

RepliCrux18-Jun-07 2:32

RepliCrux

18-Jun-07 2:32

Something like this:

private void listView1_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.R)
{
//search the list view for item
listView1.Items[0].Selected = true;
}
}

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.