Comments by DaveyM69 (Top 115 by date)

Rather than == "" it would be better to use String.IsNullOrEmpty(textBox.Text).
Also, exceptions should be more specific - ArgumentNullException would be a better choice here.

You generally only need to use fixed if the unmanaged function will mutate the data and you need it again afterwards - it prevents the GC moving the data in memory. GCHandle (when using GCHandleType.Pinned) is normally a better way for that though, or Marshal.AllocHGlobal - they both need to be freed if used so beware if you ever need them!

This is rarely a good solution, Griff's solution is the correct way to do this.

The remarks section says:
No conversions are performed. Therefore, the data retrieved must already be a single-precision floating point number.
Call IsDBNull to check for null values before calling this method.
I would start with those...

This will work only if the form loads before the timer ticks which is not guaranteed - a poor solution in my opinion.
There are several events raised by the form itself that may suffice (such as Shown) that would be more appropriate.

You're welcome :)

Is the pointer a pointer to unmanaged memory? If so, this will copy the data to a byte[] which can be serialized:
[Serializable]
public class Data
{
private byte[] data;

public Data(IntPtr handle, int length)
{
data = new byte[length];
Marshal.Copy(handle, data, 0, length);
}
}

If the List is a list of class instances then each element will just hold a reference (4 bytes 32bit, 8 bytes 64bit). The overall memory used by the app will increase by the the size of all instances combined, but the List object itself will approximately be IntPtr.Size * Count.

Good advice - I had never even thought of that :-)

"If MIDI sound sounds not realistic enough to you (which I understand; it means you have some musical hearing"
Rubbish!

Good quality professional instruments that use multiple high quality samples and MIDI generated by a musician that actually understands how the instrument (who's sound is trying to be replicated) works so can play accordingly can sound really incredibly good and discernible from an audio recording in many cases.
There is no concept of MIDI sound as it's just a digital description of a performance.

Edited to remove br tags in pre blocks as they are being displayed as plain text

Don't post your email address to a public board such as this unless you love spam!
You will receive an email notification if anyone posts a solution or comment, which will then be here for all to benifit from and not just in your email inbox.

All properties have a default value, the value depends on the type. In general, for value types it is 0 or the type's equivalent, for reference types it is null.

In the case of user controls, the default value can be set using the DefaultValue attribute, and a TypeConverter if one is needed.

OP posted:
Hi Richard,
Thanks for reply,
http://support.symbol.com/support/product/softwaredownloads.do[^]

here i find the Sample form for MK 500, .NET environment (Micro Kiosk)

Do not post further questions or statements as solutions, please either update your original question or post a comment to the person you wish to respond to.
DO NOT post your email address in a public forum unless you wish to receive spam! I have removed it for your protection. Anyone who wishes to help you can contact you through this page.

Fixed a minor typo ;-)

Forgive me if I sound rude but I am perfectly clear on how interfaces work! Don't assume that because I'm not understanding you fully that my knowledge is lacking in the language fundementals.

It seems I may have misunderstood, you see this as an alternative for passing entire form instance references? I rarely pass an entire form and certainly wouldn't to facilitate the communication of one value as the OP wanted. I use the event/delegate method for this (or keep a reference in the owner) and was trying to understand how your interface fitted into this - the answer is it doesn't. You are simply using an interface (as a parameter to a constructor or similar I assume) to couple the forms as a slightly better alternative to coupling to a specific concrete implementation of a form.

Tight coupling of this kind, even if done with an interface, is something I avoid wherever possible.

Edit: I assume you mean something like this...
public interface IOwner
{
void SetText(string text);
}

public partial class FormMain : Form, IOwner
{
public FormMain()
{
InitializeComponent();
}

public void SetText(string text)
{
Text = text;
}
}

public partial class FormOther : Form
{
private IOwner owner;

public FormOther()
: this(null)
{ }
public FormOther(IOwner owner)
{
InitializeComponent();
this.owner = owner;
}

private void SetOwnerText(string text)
{
if (owner != null)
{
owner.SetText(text);
}
}
}

"Do not reduce the idea an absurd. No. You can implement only one or, say, two." This is the bit that concerns me most. In the property or event convention, when something changes we generally set a property to a single type of value or raise an event with data of a single value - we don't pass the entire object. You on the other hand are saying to pass an entire interface with possibly many properties (or keeping a constant reference to one - I understand a delegate does this too) every time just one value has changed.

If only one thing has changed or is about to change etc, that should be the only information presented/passed IMO, there is no need for an entire interface to be given each time.

I don't disagree that yours is a convenient approach and will work well, I just fail to see any advantage over the traditional and widely used approaches that are quite adequate for all situations.

I will experiment with it however, and if you and Bill do collaberate, please let me know as I would be very interested to see exactly how you implement this in a real world situation :-)

Hi SAK, I have seen this answer of yours before and not responded as I wanted to ponder on your suggestion. However, I'm still having difficulty in seeing the benifit of using an interface over setting a property or sending a custom EventArgs depending on the direction of communication.
Interfaces are normally more suited to a particular functionality (eg IComparable) or a representation of a common object where an abstract class is not desired. While they can be used in this situation I'm not sure what we gain when passing discrete values. In fact, to ensure only the relavent data is available in a complex object such as a form we would need to create and implement many small interfaces so we only pass the interface that has the particular data required.

Correct - 5.

A couple of minor comments...
I don't like your method of blindly adding the deliminator even if it's not required and then creating an extra string by using Trim! Also, this will only take care of (with the parameterless Trim method), whitespace deliminators. You talk about maintainability, the deliminator requirement may change. This would be better IMO:

bool notFirst = false;
foreach(int number in numbers)
{
if(notFirst)
sb.Append(delimiter);
notFirst = true;
sb.Append(number.ToString());
}
txtNorth.Text = sb.ToString();

You say "//anonymous delegate is the best" - why? For readability and maintainability a good old method is far better IMO. It also allows for code reuse if needed as the method could be called from elsewhere.

It's quite obvious that he means a 'Child' form i.e. one that is instanciated by another (main in this case) as the other posters realised.
As a regular in QA you should also realise that what you posted is a comment not a solution. I'll leave it for you to ammend.

Most barcode scanners I have come across can be programmed to use a different or no suffix. All the ones in my company for example are programmed to send TAB after the scanned code.

Finally got the hyperlink to work!

Hi Luc,
True, it's just a habit I've got into from being caught out occaisionally by objects that don't implement the == and != operators. If they do iplement them they will use object.ReferenceEquals() in their equality checks against null anyway so no overhead, more readable without perhaps ;)

Gets my 5! I prefer the second option everytime.

"In my opinion, as you cannot produce really unique sound, all this is not really good to create real "analog" music good for performance, say, for writing and distributing audio CDs. If you listen MIDI music for a long time you may feel irritated by its "mechanical" sound, because all the sounds are essentially repeated many time without having unique sounds typical for life music."
I do not agree - it depends on the quality of the MIDI recording and the device(s) used for playback. I use MIDI for recording (digital) piano alongside an audio recording of vocals for a duo. The PC then plays the Piano back exactly as I played it, nothing mechanical at all about it.
This reputation comes from people using software tricks such as quantizing where not appropriate and the poor quality sound of some early MIDI instruments and most soundcards (all the built in ones!) that people use to play back on later - neither of these are the fault of MIDI.

Wrap the code in your watcher_EventArrived method in a try catch and inspect the thread ID in the catch as I suspect it will be different when the exception is thrown.
If so, refactor your code and check toolSubMn1ConfigUFD's InvokeRequired property and invoke accordingly.

Good answer - 5ed

We need to see the C++ declaration of the function and your C# P/Invoke version of it.

Or better still, an InvalidEnumArgumentException: http://msdn.microsoft.com/en-us/library/97x53xzc.aspx

Perhaps you should help us to help you by identifying the line on which the error occurs and what the error message is?

Great link Pete, very interesting.

If you 'Improve Question' you can retag. I've done this one :-)

+= adds the right hand side to the left hand side so
Resultatet += Tarningsreulstat
is the same as:
Resultatet = Resultatet + Tarningsreulstat;

By the way, int.Parse can be dangerous. Run the app and enter a normal letter...
Have a look at int.TryParse here: http://msdn.microsoft.com/en-us/library/f02979c7(v=VS.80).aspx

You need to code this yourself

This can only happen if the RunWorkerAsync is called from a non UI thread or called before the SynchronizationContext is set (normally happens when calling from a form's constructor - the Load event and beyond are fine) as an AsyncOperation is created which handles Post/PostOperationCompleted to the UI thread via the SynchronizationContext.

So why the downvote?

Without seeing a code snippet of the section that is causing the error it's impossible to help.
The normal issue is trying to get/set yourArray[Count] when the highest element is at yourArray[Count - 1].

As this isn't an answer you should have edited your original question to include the code - not posted as an answer!

Have youtried adding a call to Invalidate(); after this.Controls.Add(((ZoneItems)sender)[((ZoneItems)sender).Count - 1]);
Invalidate works in DesignMode too.

This is not an answer, it is a comment so should be posted as either a comment to an answer or as an edit to your original question.
Nobody here will give you their email address or debug your entir project.
I am deleting this fake answer.

You have posted this as an answer but in no way does your post qualify as an answer - deleted.

@SAKryukov: You are correct - I misread the documentation.
This blog explains it better than MSDN: http://www.simple-talk.com/community/blogs/andras/archive/2008/08/01/65554.aspx
Seems like there's no solution other than to check each returned result...

I would prefer << 8 to * 256 as it represents what is happening better - just a preference!

From the original question:
"If i call other forms then current form control loses focus."
Most likely Forms :-)

Nice find Roger - could be useful, for the OPs problem ContainerControl.ActiveControl will get him what he needs.

@programmer095: This is the way all processors work (as far as I know). It makes sense really. 0x0000 - 1 must be 0xFFFF so therefore for a signed 16bit value 0xFFFF must be -1.
Also, using your theory there would be 1 less value available (-32768), and there would be +0 and -0 instead...

Not required, but highly recommended!

Rewrite the 'old program' (from scratch if needed) so it doesn't require Administrator.

To complete the answer...
To obtain the value of TEMP you will need to do:
Environment.GetEnvironmentVariable("TEMP")

As you have posted your comment as an Answer, Pete will get no notification that it has been posted. You would be better reposting using the Add Comment link below his Answer and deleting this.

Hi Tim, I never got a notification of your post because you added it as an answer instead of a comment!
Did you sort this out? If not, add a comment to my post and I'll help you through it.

Where are you creating the timer?
Where are you starting the timer?

What you have posted is not an answer.
If providing more information please edit the original question.
I have done this for you so I'll delete your 'fake' answer.

When posting, ask yourself - "Am I answering the qestion?".
If yes, then post as an answer.
If no (requesting more information etc) then post as a comment.

"Or else i may fail in my subject"
If you don't understand the subject then you should fail. That is a good thing - if you haven't been dedicated enough to work at it and are prepared to cheat by copying and pasting code from the internet, you really will not enjoy it as a career and would better off finding another subject to study that actually interests and motivates you.

It's generally bad practice to expose a field directly. The field should be private and exposed by a public property. (I'm not the one who 3 voted you by the way!)

The answer is - it depends! Is the C++ function actually returning a char[] or a pointer to one? Where is the length of the array specified - in a parameter or a constant, or is it a null terminated one in which case it's really a string?
The easiest way for us to help you is if you give us the original C++ function declaration, from there it's normally pretty easy.
Alternatively, check out http://msdn.microsoft.com/en-us/magazine/cc164123.aspx, especially the 'Marshaling Text' section.

Reason for my vote of 5
Good answer!

As o isn't used outside the foreach there is no need to declare it outside. Declaring inside keeps the scope limited as it should be:
foreach(object o ...

Calling ToString() inside Console.WriteLine is not required as WriteLine calls ToString on any objects anyway to write them.

Had you highlighted the line where the error occurs and included the FULL error message we could have solved this much more easily! I have done this for you.

I've had issues with this in the past, the active TabPage resizing but not repainting properly when using Anchor or Dock. Maybe this is what the OP is getting at?
Edit: I've just checked:
1. The page doesn't resize on Maximize.
2. When Minimizing the size is reduced but when restoring from the task bar it doesn't resize. Talk about buggy!

As this isn't an answer you shouldn't have posted it as an answer!
You can edit your original post (Improve Question), I've done this for you, and if you wish to comment to an answer you've been given, use the Add Comment widget below it.

This is good except for your OnSomeValueChanged method. There are two problems.
1. There is a possible race condition. SomeValueChnged could become null between the null check and the next line where you fire the event. To guard against this, make a copy of SomeValueChanged:
EventHandler eh = SomeValueChanged;
then use eh from that point.
2. It's generally better to pass the args to the OnXxx method as a parameter and make the OnXxx method protected virtual. This makes it possible to be easily overridden later in deriving classes.

To Christian: "hideous thing to do"
I have to own up and say I normally give my fields and contructor parameters exactly the same name and use this to assign the parameters to the fields... saves all that horrible _field or m_Field stuff!

These comments do not relate to your original question. Have a look at this forum post which explains how: http://www.codeproject.com/Forums/1649/Csharp.aspx?fid=1649&select=3573386&fr=276#xx0xx
Basically, child forms raise events which are listened to by parent forms and parent forms set properties/call methods on child forms.

That isn't an answer, it's a comment to my proposed answer therefore you should use the "Add Comment" widget below the post.
If you need class level scope, just create a class level variable.

Which object creates the third form instance?

*laugh* No problem!

Look at Christian's previous comment!
If you need to respond to an answer, use the "Add Comment" widget below. The Add answer section is for answers not comments! Also, adding an answer won't alert the person you are trying to reach - Add Comment will.

Reason for my vote of 4
Although the OP didin't specify or tag as WPF he has added a solution for that situation so counts as an answer as far as I'm concerned.

pinvoke.net is a good guide - be careful though as there are many incorrect submissions on there. The most common mistake I've found is using int instead of IntPtr. This will be OK normally on 32 systems, but has a reasonably high probability of failing if ever run on a 64bit OS.
Moral: Check the signatures against those declared in the relavent C/C++ header file or MSDN page and correct if needed.

Reason for my vote of 5
Good question

To Toli:
Yeah, it's not an answer and should really have been a new question. This is the problem with a non threaded format such as QA! In this type of case IMO we should forgive the OP.

Glad you got it sorted! Strings are pesky little buggers as in .NET they are not null terminated char arrays as they are in C/C++ so pointers from the managed world are often not valid as string pointers in the unmanaged world even when using the MarshalAs attribute. StringBuilder has all this stuff taken care of deep down inside fortunately.

I have edited your post as the code was totally illegible. Now it's properly formatted it's not much better due to many glaring errors. If you are going to paste code, at least make sure it compiles!

Reason for my vote of 5
Good answer

Please don't post in the forum and Q&A as it gets messy. Pick one per question and stick with it.
C# Forum link: http://www.codeproject.com/Messages/3535838/Re-hi-can-any-one-suggest-me-quickest-optimized-wa.aspx

There is no difference in code between WinForms and Console with the following exceptions...
Move the code out of the Main method and put it in it's own new (normally not static) method with a suitable name and call that at a suitable point (after the main form's constructor has done it's thing).
Console.Write/WriteLine will write to the VS output window (View|Output) instead of a console window.

Reason for my vote of 5
Good answer

Looking at your edit...
Not possible. There has to be some look up somewhere, either the system DateTime or an independent source such as an NTP server.
If you really think your client(s) are going to rip you off, maybe you should reconsider doing business with them at all.

Nasty! Killing processes is almost never the correct thing to do, especially when it's a basic design issue that can be fixed through a little code alteration.

For future reference, you should have posted this as a comment to the answer provided. Add Answer is for answers only, Submit Comment is for comments and further discussion.

Form2 should have a property (or properties) that can be set after instanciation from form1 (but before being shown) and then either...
form2 creates form3 and does the same
or
form2 raises an event and in the handler form1 creates & does it's thing with form3

"Or just rip the CAPS LOCK key off your keyboard" - my kind of solution!

we need to be able to vote on comments - 'gainy decompression' has gotta be worth a 5!

ROFL - Good point!

Fair enough. Under the CPOL as I understand it you can use it (change it if needed) and give it away if you so wish so long as you retain any copyright notices in the code and don't pass those sections as your own work.
CPOL here: http://www.codeproject.com/info/cpol10.aspx

"not advisable from programming point of view"
What other point of view is there?

Have a look at this from the same section:
http://msdn.microsoft.com/en-us/library/dd797971(v=VS.85).aspx

Please post comments as comments not as an answer!

There is no concrete answer - take a modern browser such as IE or FF. They both use an SDI with a tabbed interface. This could be equally be done with separate windows instead of tabs for an MDI. Which one you prefer or is better for your situation only you can decide.

WaveInGetNumDevs gets all audio inputs on the system. If you have multiple soundcards then all the inputs are added together. To determine which is which you need to examine their capabilities.
Microphone and line in are part of a soundcard, they are not separate.

I (and I suspect most other users here) haven't used 'Peachtree' so I have no idea what you mean. If you explain more clearly what you want and why existing controls can't do it we may be able to help!

If using BackgroundWorker.ProgressChanged event it will already be on the UI thread so no need to Invoke ;-)

Please use the Add Comment link below a post to reply to the poster.

John has given you the procedure - coding it is up to you. It's very easy. Have a go and if you get stuck, post the relevant code you have and any errors/exceptions you are getting and we will be glad to help.

I have edited your post so it makes sense and formatted it - however, both the original and your suggestion will produce identical results (if true, but your 'improvement' will not set the Checked property to false when required).

This is an English speaking site. I would suggest editing your question so it can be read by the site's members or posting on a site based in your own country. I am not being 'languagist', but it's unlikely that many will be able to help you if they can't understand the question!