C# Discussion Boards - CodeProject

Thomas Weller2-Jul-09 6:07

2-Jul-09 6:07

You could use reflection to enumerate over all the desired members of a class - like described in the post below. Alternatively simply implement a method object[] GetAllObjects() that returns everything you need. For serialization use the Serializable attribute and eventually the ISerializable interface (see here^ and here^).

Regards
Thomas

www.thomas-weller.de

Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning.
Programmer - an organism that turns coffee into software.

Re: Enumerate Custom Class

Dowse2-Jul-09 6:10

Dowse

2-Jul-09 6:10

Thomas

I will read up on reflection. It seems to be what I was after.

Thank you.

Re: Enumerate Custom Class

Luc Pattyn2-Jul-09 5:47

Luc Pattyn

2-Jul-09 5:47

Hi,

As Thomas said enumerators is not what you need here.
You need Reflection, which can give you access to all the data fields, constructors, methods, properties of your class.

This is an example listing all the known colors in the SystemColors class:

Assembly asm=Assembly.GetAssembly(Color.White.GetType());
Type type=asm.GetType("System.Drawing.SystemColors", true);
PropertyInfo[] pis=type.GetProperties();
int n=pis.Length;
log("There are "+n+" properties");
foreach (PropertyInfo pi in pis) {
    Color c=(Color)pi.GetValue(null, null); // get the SystemColor
    log(pi.Name+" = "+c.ToString());
}

BTW: you can only get information on class members, not on local variables inside some method.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

DISCLAIMER: this message may have been modified by others; it may no longer reflect what I intended, and may contain bad advice; use at your own risk and with extreme care.

Re: Enumerate Custom Class

Dowse2-Jul-09 6:03

Dowse

2-Jul-09 6:03

Thank to all that responded to my post.

Luc, I think I can re-work your example to give me what I was after.

Thank you.

Re: Enumerate Custom Class

Dowse2-Jul-09 7:01

Dowse

2-Jul-09 7:01

Luc, I managed to re-work your example to give me just what I was after.

Thanks for putting me on the right track:

private void ShowData()
        {
            Type type = typeof(MyClass);
            FieldInfo[] fi = type.GetFields();

            foreach (FieldInfo info in fi)
            {
                Debug.WriteLine(info.Name + " = " + info.GetValue(varMyClass));
            }
        }

varMyClass is a variable of type MyClass.

Thanks to all who helped.

modified on Thursday, July 2, 2009 1:41 PM

Re: Enumerate Custom Class

DaveyM692-Jul-09 5:58

DaveyM69

2-Jul-09 5:58

A quick google found this[^] which may be along the lines of what you're looking for?

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)
Why are you using VB6? Do you hate yourself? (Christian Graus)

Re: Enumerate Custom Class

harold aptroot2-Jul-09 6:44

harold aptroot

2-Jul-09 6:44

public class MyClass : IEnumerable<put type here> //IEnumerable<t> is better (no boxing)
{
public System.DateTime datStart; //Schedule start date
public System.DateTime datEnd; //Date of final occurrence (#1/1/1900# if N/A)
public int intParam1; //Various Uses
public int intParam2; //Various Uses
//Other fields remove for clarity

//Constructor
public MyClass()
{
//Set defaults for new MyClass()
datStart = new DateTime(1900, 1, 1);
datEnd = datStart;
intParam1 = -1;
intParam2 = -1;
}

public IEnumerator<put type here> GetEnumerator()
{
yield return someStuff; //put more of them here possible in a loop, the compiler will make a state machine out of it
}

IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator(); //this does not loop, it calls the other GetEnumerator
}
}

Threading

Wogboiii2-Jul-09 4:23

Wogboiii

2-Jul-09 4:23

Can you use threading without a static method?

Re: Threading

Luc Pattyn2-Jul-09 4:26

Luc Pattyn

2-Jul-09 4:26

Hi,

the Main() method of an app has to be static, that is where the app starts.
Apart from that, no method has to be static.

I typically create a "Job" class that holds the job's parameters and then creates a thread and runs it,
nothing static in there.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

DISCLAIMER: this message may have been modified by others; it may no longer reflect what I intended, and may contain bad advice; use at your own risk and with extreme care.

Re: Threading

led mike2-Jul-09 4:36

led mike

2-Jul-09 4:36

Wogboiii wrote:
Can you use threading without a static method?

I don't see any static methods other than main in the example code in the documentation for BackgroundWorker[^], do you?

Re: Threading

DaveyM692-Jul-09 6:01

DaveyM69

2-Jul-09 6:01

Or in the BGW's code[^].

Re: Threading

Thomas Weller2-Jul-09 5:48

Thomas Weller

2-Jul-09 5:48

Sure...
The static keyword has nothing to do with how the code is executed, but only with where it lives (instance or type). Static/not static is simply irrelevant when it comes to different threads.

In the end, it's all bytes that run through the processor, no matter where they come from...

Regards
Thomas

Re: Threading

Paulo Zemek2-Jul-09 8:56

Paulo Zemek

2-Jul-09 8:56

I think the original poster saw an example using a static method to start a new thread and thought it was a requisite.

Datagridview...

Isaac Gordon2-Jul-09 2:55

Isaac Gordon

2-Jul-09 2:55

Hi experts
i am using visual studio 2005 and sql server 2005
i am working on winform.when i want to fill the datagrid view simultaneous
show the .gif picture that show loading of grid.
but when i run it gif is not working. it run work when the grid fill Completely.then how i can fix this problem so that both grid and .gif work
simultaneous.
Thank u
Dinesh

Re: Datagridview...

Henry Minute2-Jul-09 4:01

Henry Minute

2-Jul-09 4:01

Do you mean "show the .gif picture that show loading of grid." use the .gif like a progress bar, or similar to the images shown during a file copy operation?

Henry Minute

Do not read medical books! You could die of a misprint. - Mark Twain
Girl: (staring) "Why do you need an icy cucumber?"
“I want to report a fraud. The government is lying to us all.”

Re: Datagridview...

musefan2-Jul-09 4:15

musefan

2-Jul-09 4:15

look at the BackgroungWorker[^] component

What the issue is is that your form is not being updated until the load code has completed. You could try Form.Refresh(); every now and then during your loading. But I would strongly suggest you go for a background worker

Life goes very fast. Tomorrow, today is already yesterday.

Wrting Image data in Mifare 1k card

GauravKP2-Jul-09 2:43

GauravKP

2-Jul-09 2:43

hi....
I have a code in C# by which i can write string data in Mifare 1k card.
But the problem arises when i tried to write IMAGE file .

Can someone tell me how to use byte array so that i can do my task?

thanx...

Anand (delhi)

Re: Wrting Image data in Mifare 1k card

Rajesh R Subramanian2-Jul-09 3:07

Rajesh R Subramanian

2-Jul-09 3:07

I don't even want to know what an Mifar 1k card is, but, the card as such is such not supposed to know if you're writing text or anything else into it. So, just write the contents of the image in binary format into it.

Also, try to be more specific in the future.

It is a crappy thing, but it's life -^ Carlo Pallini

what do i have to do next

j4ck1we2-Jul-09 2:20

j4ck1we

2-Jul-09 2:20

Hi,
I need some suggestions on what should I learn
Till now I know about: arrays, lists, queue (FIFO),(LIFO), sql databases...

what should I learn next.. The problem is that I dont know how to connect my program to the internet and get information from there etc.

any tutorial on how to do this thing?

Re: what do i have to do next

dojohansen2-Jul-09 2:27

dojohansen

2-Jul-09 2:27

Try searching the articles for "webrequest" and that might get you started.

Re: what do i have to do next

musefan2-Jul-09 2:34

musefan

2-Jul-09 2:34

Actually, It would be better to look at the System.Net.WebRequest classes instead Laugh | :laugh:

Life goes very fast. Tomorrow, today is already yesterday.

Re: what do i have to do next

musefan2-Jul-09 2:30

musefan

2-Jul-09 2:30

j4ck1we wrote:
queue (FIFO),(LIFO)

I believe stack is the word you are looking for for (LIFO)

j4ck1we wrote:
what should I learn next..

It depends on what you want to do...

If you are looking at working with data across a network then there is the System.Net[^] classes that may be of interest. Thou first I would suggest taking a good look at the
System.IO[^] classes and get a good understanding of how file streams work.

Life goes very fast. Tomorrow, today is already yesterday.

Re: what do i have to do next

j4ck1we2-Jul-09 7:32

j4ck1we

2-Jul-09 7:32

Well I'm thinking of building a small app that get some info from a page (search for links in it and clicking etc.)
What things could help me do this?

IOException and Number formatting

Megidolaon2-Jul-09 1:55

Megidolaon

2-Jul-09 1:55

I'm writing a small program to help me sort my thousands of images.
But whenever I want to rename a file, I get the following error:
The process cannot access the file because it is being used by another process.

I use the following code for it

private void B_Rename_Click(object sender, EventArgs e)
        {
            L_Status.Text = "";
            File.Move(Path.GetFullPath(images[current]), Path.GetFullPath(TB_New_Name.Text));
            L_Status.Text = "image '" + images[current] + "." + extension + 
            "'\r\nhas been renamed to\r\n'" +
            TB_New_Name.Text + "." + extension + "'";
            images[current] = TB_New_Name.Text;
        }

images is the string list holding the file names, current is the current index and extension is the file extension.

My other problem is the number formatting.
The images should be named with numbers, but since windows sorting is strictly text based, 2 would come after 10.
So, I tried the string.Format method to name the images 001, 002, etc., but it doesn't quite work.

public F_Main()
        {
            InitializeComponent();
            files = Directory.GetFiles(dir);
            this.Text = string.Format("{0:00}", 1);
            this.Text += " - ";
            this.Text = string.Format("{0:00}", 12);
            this.Text += " - ";
            this.Text += string.Format("{0:00}", 120);
         }

I thought this code would display "001 - 012 - 120" in the form title, but instead it onlydisplays "12 - 120"

Thanks.

Re: IOException and Number formatting

Luc Pattyn2-Jul-09 2:02

Luc Pattyn

2-Jul-09 2:02

Hi,

1. there are a couple of ways to keep a file "in use by another process", and you should, for once, not take "another process" literally. Here are some:
- another process has opened the very same file
- for text files that other process could be an automatic indexer
- for several extensions that other process could be an antivirus checking a newly created file
- MOST LIKELY IN YOUR CASE: an image loaded with Image.FromFile() remains locked as long as the image lives.

2. numeric format "D3" would always use at least 3 characters, filling with leading zeroes.

Smile | :)

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DISCLAIMER: this message may have been modified by others; it may no longer reflect what I intended, and may contain bad advice; use at your own risk and with extreme care.

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