Re: Help with syntax. Re: one to many class association [modified] - C# Discussion Boards

Re: one to many class association

24-Aug-06 4:57

hi,

I have a class association generated from an xsd file. There is a one to many relationship that exists between the classes Order and Product.
I can set the properties for order like this: Order.Number = 1;

I can create a new instance of Products like this:
Products x = new Products();
x.name="blabla";
x.type="blabla";

now the problem is that I cannot add a Product to my order class.
I'm not sure how. plus I should be able to add multiple products to this class. The syntax is like this in my Order class:

*******************************************
private Product[] product Field;

/// <remarks>
[System.Xml.Serialization.XmlElementAttribute("Product")]
public Product[] Product {
get {
return this.productField;
}
set {
this.productField = value;
}
}
***********************************

Does anyone know the syntax to do this? or is it even possible?
I'm losing it. I've been trying to get this forever....

Please write back if you know the answer? Thanks if you do.

ChaciMulch

beatles169224-Aug-06 5:26

not working still. Re: one to many class association [modified]

24-Aug-06 5:26

hi,
You can add a method to your Order class called AddProduct as follows:

<br />
class Order<br />
{<br />
.<br />
.<br />
.<br />
public void AddProduct(Product product)<br />
{<br />
ArrayList products=new ArrayList(this.productField);<br />
products.Add(product);<br />
this.productField=(Product[])products.ToArray(typeof(Product));<br />
}<br />
}<br />

Since you are storing products in an array you can not add an item to it, therefor you should use an ArrayList to add an item to the array and to cast it to the array again

Regards

chacimulch24-Aug-06 8:43

Re: not working still. Re: one to many class association

24-Aug-06 8:43

Thanks so much.. Its almost working now but I needed one change.

In the first line I just had to take out the 'this.productField'
in order to get it to work. (not sure why)

it will add one object, but if i try to add another one, it just overwrites
the first one. i need to add multiple products per order. am i doing something wrong?

Thanks Again.

Mulch

-- modified at 15:54 Thursday 24th August, 2006

beatles169224-Aug-06 21:05

Help with syntax. Re: one to many class association

24-Aug-06 21:05

Hi If you take out the first line you will lose other products that have been added to your array.You should add those items too.
Instead of

<br />
ArrayList products=new ArrayList(this.productField);<br />

write:

<br />
ArrayList products=new ArrayList();<br />
products.AddRange(this.productField);<br />

Although both methods should result the same thing ( added products so far,should be added to the ArrayList).
There's another way that I don't like and that's

<br />
ArrayList products=new ArrayList();<br />
foreach(Product item in this.productField)<br />
products.Add(item);<br />

please let me know if it's not working again
Regards

chacimulch25-Aug-06 2:36

Re: Help with syntax. Re: one to many class association

25-Aug-06 2:36

I still can't get it to work. I may be adding these lines in the wrong order.
this is how I tried implementing it:

ArrayList products = new ArrayList();
products.AddRange(this.productField);
products.Add(code);
this.productField = (Product[])products.ToArray(typeof(Product));

At least now I'm getting some sort of error in my browser. It is below. It seems like 'this.productField' is set to null at this point or something like that. I'm just confused. I'm not really following exactly what is happening here. I didn't think it would be this hard when I started. I created this class from an xsd and I thought that i would be able to add multiple sub class items automatically.

Any other ideas to what I'm doing wrong?

someone else said to try using a collection but I've never done that either and I just need to get this working as fast as possible. Thanks.

System.ArgumentNullException: Collection cannot be null.
Parameter name: c
at System.Collections.ArrayList.InsertRange(Int32 index, ICollection c)
at System.Collections.ArrayList.AddRange(ICollection c)
at RepairRequests.AddOpCode(OperationCode code) in c:\Inetpub\wwwroot\ASIAPI\App_Code\RepairOrder.cs:line 515
at Service.GetRepReq() in c:\Inetpub\wwwroot\ASIAPI\App_Code\Service.cs:line 134
at Service.GetRO() in c:\Inetpub\wwwroot\ASIAPI\App_Code\Service.cs:line 62
at Service.GetROData(String RO_ID) in c:\Inetpub\wwwroot\ASIAPI\App_Code\Service.cs:line 30

beatles169225-Aug-06 3:03

Re: Help with syntax. Re: one to many class association [modified]

25-Aug-06 3:03

I see

That's because productsField is null for the first time that you want to add a product
then wrtie:

<br />
....<br />
if(productField!=null) products.AddRange(productField);<br />
....<br />

or you can make it empty (instead of null):

<br />
...<br />
private Product[] productField=new Product[]{};<br />
...<br />

and there would be no need to check if productField is null in AddProduct routine.
I Prefer the second approach.
Regards

chacimulch25-Aug-06 3:51

Re: Help with syntax. Re: one to many class association

25-Aug-06 3:51

Holy crap it's working. Cool | :cool:

Thanks so much for your help and you SPEEDY responses.

I've never worked with classes in this fasion before and I'm still trying to understand what is going on here because I want to learn. Maybe you could explain this for me? Also since I don't really understand this, is there going to be multiple array lists created and cause memory issues. It seems to me like it will create a new list every time i really just want to add an object to the same list????

so this is decaling product as an empty array of type products?
private Product[] productField=new Product[]{};

new array list?
ArrayList repReqs = new ArrayList();

confusion here: to me this seems like it's creating a range of arrays?
shouldn't it be a collection of class objects?
repReqs.AddRange(this.repairRequestsField);

confusion here: now your adding an object to your array list, but how does it
know to use the new range?
repReqs.Add(rr);

confusion here: basically no clue.
this.repairRequestsField = (RepairRequests[])repReqs.ToArray(typeof(RepairRequests));

I really want to get a better grasp on some more complex c# aspects like this. Do you have any suggestions for good books?

thanks.

-- modified at 9:54 Friday 25th August, 2006

beatles169225-Aug-06 12:10

Re: one to many class association

25-Aug-06 12:10

Hi Yse you can declare an empty array using this syntax:

<br />
object[] arr=new object[]{};<br />

Well an arraylist is a collection object that you can add other obejcts to it(using its Add method) and it has a lot of use,you can enumurate it using its enumurator and C# foreach keyword like this:

<br />
foreach(object obj in myArrayList)<br />
{<br />
do somthing with obj;<br />
}<br />

When you use AddRange method all the members of the passing array will be added to your arraylist it's something like:

<br />
foreach(object item in myArray)<br />
{<br />
myArrayList.Add(item);<br />
}<br />

We did this here because we wanted to save the current state of our object and then add a new item to our arraylist.
Finally we convert our arraylist into a Product array again.
First we make an array from out arraylist using its ToArray() method telling it that the type of stored items is Product (typeof(Product)) then we cast our array (that so far is an object array) to a product array using (Product[]);
So we've done two tasks at one line.We could write it like this:

<br />
object[] array=myArrayList.ToArray(typeof(myClass));<br />
myClass[] convertedArray=(myClass[])array;<br />

There are a lot of good books about C# and .Net programming but what I found really useful are MSDN and this site(Code Project) you can learn a lot of things about C# and programming here.
Wrox Programming C# is a good book.
There's another book that I like "Teach yourself object oriented programming in 21 days" It's written in java though.
Anyway I'm glad that you could solve your problem and If there's anything else just I will be glad if I can help.
Regards

Nader Elshehabi24-Aug-06 10:51

Nader Elshehabi

24-Aug-06 10:51

Hello

If you use .Net 2.0 then instead of using arrays, you should use List<product> Generic colection.

If you use .Net 1.1, then use System.ArrayList instead, as you want your array to be dynamic and grows as you add to it.

I prefered List<product> as it's type specific generic collection. Yet ArrayList will do fine.

Regards Rose | [Rose]

using Sission by c#

mhattiyah24-Aug-06 4:46

mhattiyah

24-Aug-06 4:46

Session("dt").rows(i)("trans_no").ToString by vb
after conver to c#
Session("dt").rows(i)("trans_no").ToString();
not working
how it don ?

m_attiea

Re: using Sission by c#

ToddHileHoffer24-Aug-06 5:10

ToddHileHoffer

24-Aug-06 5:10

if dt is a datatable then...
DataTable dt = (datatable) session["dt"];
dt.rows[i].["trans_no"].ToString();

how vital enterprise application are for proactive organizations leveraging collective synergy to think outside the box and formulate their key objectives into a win-win game plan with a quality-driven approach that focuses on empowering key players to drive-up their core competencies and increase expectations with an all-around initiative to drive up the bottom-line. But of course, that's all a "high level" overview of things
--thedailywtf 3/21/06

inconsistency in virtual dir

Kunal P24-Aug-06 4:31

Kunal P

24-Aug-06 4:31

hey

i m creating a web appln in c#. recently i implemented session var in my website to enhance security.. but the problem is that after publishing this website on IIS(inetpub\wwwroot..), i opened it from my browser.. the sessions are not at all working..

even after entering correct username and pass.. i m redirected to login page again and again..

on the other hand when debugging the application, it works perfectly well.. m using visual web dev exp 2005

please help

Kunal Piyush

Re: inconsistency in virtual dir

Ennis Ray Lynch, Jr.24-Aug-06 9:15

Ennis Ray Lynch, Jr.

24-Aug-06 9:15

Sounds like either A) A windows Permissions error as debug is run in Admin or B) The code is not synced.

On two occasions I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question. - Charles Babbage

Re: inconsistency in virtual dir

Kunal P24-Aug-06 20:03

Kunal P

24-Aug-06 20:03

well.. as i said before implementing session variables..the thing was perfectly fine..

but still how do i go bout fixing the errors u said...

Kunal Piyush

Re: inconsistency in virtual dir

Guffa24-Aug-06 22:42

Guffa

24-Aug-06 22:42

Please don't cross post.

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

Doh! Regular Expressions and C# Strings [modified]

Brent Lamborn24-Aug-06 4:24

Brent Lamborn

24-Aug-06 4:24

Sorry to post this but, here goes.

All of the coding I've ever done, and gotten paid for it, has been VB. I'm working on a project now that I decide to do in C#. It's a breath of fresh air, let me tell ya. It reminds of my days in college doing C++ and makes me realize how brain dead doing VB can make a guy!

Anyway, what's with this escape character stuff in C# strings? I'm having a heck of a time coming up with a regular expression that will match IP addresses with leading zeros, and I think my problem may be the escape character "/". I tried replacing / with // but still no matches. In fact every regex I found on the web for IP addresses failed to match.

Here is the function:

private void RangeCheck()
       {
           String sLine = "";
           String  sIPMatcher = "(\\[0-9]{1,3})\\.(\\[0-9]{1,3})\\.(\\[0-9]{1,3})\\.(\\[0-9]{1,3})";

           RegexStringValidator test = new RegexStringValidator(sIPMatcher);
           StreamReader sr = new StreamReader("c:/UniqueIPaddr_list.csv");

           while (!sr.EndOfStream)
           {
               sLine = sr.ReadLine();

               try
               {
                   test.Validate(sLine);
                   if (IPList.CheckNumber(sLine))
                   {
                       lstBox.Items.Add(sLine);
                   }
               }
               catch
               {
               }
           }
       }

IPList is a class I borrowed from Bo's article here[^].

And here is an example of one of 10,000+ IP address in the .csv file: 00x.0xx.xxx.0x0
where x is any number 1-9 (didn't want to disclose an acutal IP).

No matter what I try, no matches occur. D'Oh! | :doh:

Is it my lack of C# skills, or just use of an incorrect regex?

-- modified at 10:25 Thursday 24th August, 2006

"Half this game is ninety percent mental." - Yogi Berra

If you can read thank a teacher, if you can read in English, thank a Marine.

M y and h don't work so well due to m addiction to caffeine and m in abilit to to set a cup down uprigt.

Coding C#24-Aug-06 4:38

Coding C#

24-Aug-06 4:38

Hi,

try this.

(\d{1,3}\.){3}\d{1,3}

hope this works.

Nitin...

User 665824-Aug-06 5:31

User 6658

24-Aug-06 5:31

This will also match invalid IPs like 999.999.777.444

This one will match only well formed IPs:

^(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])$

(got that one from Regexlib.com)

regards

modified 12-Sep-18 21:01pm.

coolestCoder24-Aug-06 4:42

coolestCoder

24-Aug-06 4:42

Hi,

dotnethead wrote:
String sIPMatcher = "(\\[0-9]{1,3})\\.(\\[0-9]{1,3})\\.(\\[0-9]{1,3})\\.(\\[0-9]{1,3})";

You can use

String sIPMatcher = @"(\[0-9]{1,3})\.(\[0-9]{1,3})\.(\[0-9]{1,3})\.(\[0-9]{1,3})";

@ character considers all characters to be text inside " "
Try it !

<marquee>"A good programmer is someone who looks both ways before crossing a one-way street." -- Doug Linder

Anant Y. Kulkarni

Re: Doh! Regular Expressions and C# Strings [modified]

Brent Lamborn24-Aug-06 6:26

Brent Lamborn

24-Aug-06 6:26

Anant Y. Kulkarni wrote:
@ character considers all characters to be text inside " "

Golden, just what I was looking for!
Unfortunately Anant, your regex did not match. I think it must be the leading zeros?

The only regex that matched anything was:

String sIPMatcher = @"(\d{1,3}\.){3}\d{1,3}";

Although it will match 999.999.999.999, I know for sure that all of the IP's containing all numbers are good ones. There are however, ones with letters in them, which is why I need this regex.

Thanks for all the help....it was nice to come back to all the responses after a long meeting!

coolestCoder24-Aug-06 19:52

coolestCoder

24-Aug-06 19:52

Hi,

dotnethead wrote:
Unfortunately Anant, your regex did not match.

Actually i didnt changed the regex. I only suggested a part of solution for your escape character problem. Sorry, that i was not clear what i have posted.

-- modified at 1:55 Friday 25th August, 2006

<marquee>"A good programmer is someone who looks both ways before crossing a one-way street." -- Doug Linder

Anant Y. Kulkarni

Coding C#24-Aug-06 20:19

Coding C#

24-Aug-06 20:19

Hi,

this is the modified version of my previous regex which i posted.

Regex rx =new Regex(@"^(\d{1,3}?\.){3}\d{1,3}$");

this will check the proper format for ip.
but this will also match no.s greater than 255.
so what you can do is first apply above regex expression for valid format and if found correct you can split the ip and check for each part no. is not greater than 255.

hope this works.

Nitin...