C# Discussion Boards - CodeProject

Re: How do I write to this class?

Not Active11-Jan-09 16:29

Not Active

11-Jan-09 16:29

e40s wrote:
questions as stupid?

not questions, only the people who ask them without knowledge. Poke tongue | ;-P

e40s wrote:
I would prefer that you not reply to any questions I post in the future.

I would prefer you not asking basic knowledge questions. Guess we can't get what we wish for.

only two letters away from being an asset

Re: How do I write to this class? [modified]

Luc Pattyn11-Jan-09 16:54

Luc Pattyn

11-Jan-09 16:54

Hi,

I would like to suggest you buy an introductory book on C# and work your way through it.

That will take a few days but it will provide you with all the basic information you are going to need anyway, in a logical order and a consistent terminology; it will teach you all the new concepts and make you feel comfortable with C# much faster than any other way. So go to a book store (or visit Amazon, I prefer the book store though), look at a couple of books, and choose the one that looks most promising to you.

That is what I do for any new language or technology I want to learn.

The refinement is: buy two books, a tutorial and a reference book; and study the tutorial.
The reference book is not absolutely necessary, you can Google or use MSDN for detailed info;
but nothing can replace the tutorial or introductory book.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

I use ListBoxes for line-oriented text, and PictureBoxes for pictures, not drawings.

modified on Friday, June 10, 2011 12:34 PM

Re: How do I write to this class?

Pete O'Hanlon11-Jan-09 8:43

Pete O'Hanlon

11-Jan-09 8:43

This is a static class, so it seems that you must have a static method in there that returns an initialized version of the class. When you type in your class, type in PDFToImage pdf2i = PDFToImage. Intellisense should return the method you need.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

My blog | My articles | MoXAML PowerToys

Re: How do I write to this class?

e40s11-Jan-09 9:23

e40s

11-Jan-09 9:23

Thanks for replying to my post. The IntelliSense dropdown contains not a single line of pdfbox-related object at all. I wish it did. The dropdown doesn't even list pdfbox itself.

I don't know if it's because these DLLs were IKVMed from Java bytecode or what.

But--oddly in the same IDE--the mouseover can inform the user, by mouseover caption, that PDFToImage is part of the org.pdfbox namespace. That much shows up.

(I'm using SharpDevelop.)

Re: How do I write to this class?

Not Active11-Jan-09 9:29

Not Active

11-Jan-09 9:29

I think you should familiarize yourself with the environment and tools before proceeding; i.e. Pick up a basic .NET book and read a little.

only two letters away from being an asset

Password protect information in an application

Karmendra Suthar11-Jan-09 7:06

Karmendra Suthar

11-Jan-09 7:06

I am developing an application in Visual Studio C# 2008 Express Edition.

I need to have a password protected access to a dialog box containing a check box. the value of the check can be only modified if password is provided. The value of the check box should be always available to the application to check the status.

Please tell me how can I accomplish having a password protection to such data.

Thanks,
Karmendra

Re: Password protect information in an application

Not Active11-Jan-09 8:30

Not Active

11-Jan-09 8:30

Add login to the application and check the credentials when displaying the dialog. It isn't that difficult and there are plenty of examples here and elsewhere. What have you tried so far?

only two letters away from being an asset

Help Creating Sql Class

Calferreira11-Jan-09 7:06

Calferreira

11-Jan-09 7:06

Hi there , i'm trying to create a class in C# to use my Sql operations but i'm facing some problems.
Although i'm using the code to import SQL objects(using system.data.sqlclient;) i can't declare variables such as Sqlcommand or sqlclient for ex.That way the class get's kind meaningless.How can i use them?

Thanks for your help and pacience as you will figure it out i'm learning C# i was a Vb6 coder.

Re: Help Creating Sql Class

User 665811-Jan-09 7:41

User 6658

11-Jan-09 7:41

You mean the compiler doesn't find the SqlCommand and other types? You need to add a reference to the System.Data.dll. In Visual Studio right click on the project and select "Add Reference".

regards

modified 12-Sep-18 21:01pm.

Re: Help Creating Sql Class

Calferreira11-Jan-09 8:09

Calferreira

11-Jan-09 8:09

Already done that.
You can see better here http://img171.imageshack.us/my.php?image=screenshotvz3.jpg[^]

Re: Help Creating Sql Class

User 665811-Jan-09 8:14

User 6658

11-Jan-09 8:14

You also have to import the namespace (also just typing SqlCommand into the editor VS will automatically suggest you to import the necessary namespace):

http://msdn.microsoft.com/de-de/library/system.data.sqlclient.sqlcommand(VS.80).aspx[^]

using System.Data.SqlClient;

modified 12-Sep-18 21:01pm.

Re: Help Creating Sql Class

Calferreira11-Jan-09 10:59

Calferreira

11-Jan-09 10:59

Thanks!

ObservableCollection Constructor

Michael Sync11-Jan-09 6:20

Michael Sync

11-Jan-09 6:20

I'm facing some problems with ObservableCollection constructor..

Any idea why this code is not working?

entity.Currencies = new ObservableCollection<CurrencyEntity>(CurreniesList.Where( c => c.IsSelected));

Note:

1. entity.Currencies is ObservableCollection<CurrencyEntity>().
2. CurrenciesList is ObservableCollection<CurrencyEntity>().
3. CurrencyEntity class has a proprety called "IsSelected".

Thanks in advance.

Thanks and Regards,
Michael Sync ( Blog: http://michaelsync.net)

Re: ObservableCollection Constructor

S. Senthil Kumar11-Jan-09 6:40

S. Senthil Kumar

11-Jan-09 6:40

ObservableCollection < T > 's constructor takes a List < T >, and not IEnumerable < T >, presumably because only then can it "observe" addition and removal of elements. Simply wrapping the result of CurrenciesList.Where in a list should solve the problem.

new ObservableCollection <CurrencyEntity>(
                new List<CurrencyEntity>(currenciesList.Where(c => c.IsSelected)));

Regards
Senthil [MVP - Visual C#]
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Re: ObservableCollection Constructor

Michael Sync11-Jan-09 7:21

Michael Sync

11-Jan-09 7:21

Hi Senthil,

Thanks but I'm still getting the error. There are 3 constructors[^] in ObservableCollection.

IEnumerable[^] is one of them.

Or, Am I missing something??

Thanks and Regards,
Michael Sync ( Blog: http://michaelsync.net)

Re: ObservableCollection Constructor

S. Senthil Kumar11-Jan-09 8:24

S. Senthil Kumar

11-Jan-09 8:24

My bad, I missed out the third overload.

Can you paste the error that you are getting?

[EDIT] .NET 3.0 has only two overloads (http://msdn.microsoft.com/en-us/library/ms658737(VS.85).aspx[^])

Regards
Senthil [MVP - Visual C#]
_____________________________
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Re: ObservableCollection Constructor

Michael Sync11-Jan-09 8:45

Michael Sync

11-Jan-09 8:45

The error message is like it doesn't a constructor that takes 1 argument.

I'm using 3.5.... Am i referencing the wrong dll or need to import some namespaces? it's very strange

Thanks and Regards,
Michael Sync ( Blog: http://michaelsync.net)

Re: ObservableCollection Constructor

S. Senthil Kumar11-Jan-09 8:58

S. Senthil Kumar

11-Jan-09 8:58

What does hitting F12 (Go to Definition) on the ObservableCollection show?

Regards
Senthil [MVP - Visual C#]
_____________________________
My Home Page |My Blog | My Articles | My Flickr | WinMacro

Re: ObservableCollection Constructor

User 665811-Jan-09 7:51

User 6658

11-Jan-09 7:51

This sounds a bit strange, because this is working for me:

public class CurrencyEntity
{
	public bool IsSelected
	{
		get { return true; }
	}
}

This is just a stub, and here's the code:

List<CurrencyEntity> c1 = new List<CurrencyEntity>() { new CurrencyEntity() };
ObservableCollection<CurrencyEntity> ob = new ObservableCollection<CurrencyEntity>(c1.Where(c => c.IsSelected));

modified 12-Sep-18 21:01pm.

Re: ObservableCollection Constructor

Michael Sync11-Jan-09 8:45

Michael Sync

11-Jan-09 8:45

I will try again and let you know. it's very strange..

Thanks and Regards,
Michael Sync ( Blog: http://michaelsync.net)

Re: ObservableCollection Constructor

Michael Sync12-Jan-09 4:49

Michael Sync

12-Jan-09 4:49

Thanks. I think it doesn't work because of Silverlight. I'm using Prism v2 (with multi-targeting feature). so, i need to create the class in SL project and link that class from wpf. that's why the code doesn't work.

Thanks for your help.

Thanks and Regards,
Michael Sync ( Blog: http://michaelsync.net)

List<T>.AddRange and ArgumentException?

User 665811-Jan-09 4:05

User 6658

11-Jan-09 4:05

Hi everyone,

I'm experiencing a strange exception in the List<T>.AddRange[^] method.
Sometimes (maybe in 1 out of 100 runs with the same data) I get a System.ArgumentException inside AddRange that the destination array is not large enough for the collection. Here's what I'm doing:

if (itemsToAdd > 0)
{
   existingItems.AddRange(itemsToAdd); // boom
   itemsToAdd.Clear();
}

Now MSDN clearly states:

If the new Count (the current Count plus the size of the collection) will be greater than Capacity, the capacity of the List<(Of <(T>)>) is increased by automatically reallocating the internal array to accommodate the new elements, and the existing elements are copied to the new array before the new elements are added.

Did anyone else experience this weird behaviour?

regards

modified 12-Sep-18 21:01pm.

Re: List<T>.AddRange and ArgumentException?

Not Active11-Jan-09 4:16

Not Active

11-Jan-09 4:16

Sounds like it is a problem of the allocation of new memory to expand the collection is slower than expected by the framework. Have you tried to set the expected number of elements when you create the List? You may not have an exact number, but an large estimate should prevent this from occurring. The TrimExcess method can free up any extra resources after you've filled the List

only two letters away from being an asset

Re: List<T>.AddRange and ArgumentException?

User 665811-Jan-09 4:26

User 6658

11-Jan-09 4:26

Mark Nischalke wrote:
Have you tried to set the expected number of elements when you create the List?

That's what I will actually try next. But since the error is quite hard to reproduce I'm not sure if this will help. I do have an estimated number how many items the list will contain, so I could set it. It's a very small number of items, so I don't think it's some sort of memory problem (but in this case I think OutOfMemoryException would be the proper one).

modified 12-Sep-18 21:01pm.

Re: List<T>.AddRange and ArgumentException?

Not Active11-Jan-09 4:33

Not Active

11-Jan-09 4:33

I didn't say it was a memory problem per se. If the framework were trying to place a element into the collection before the memory allocation and redistribution had completed, then it would be an ArguementExcepetion, not an OutOfMemoryException.

only two letters away from being an asset

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