Re: When To Use 'this' in C# - C# Discussion Boards

Jamal Abdul Nasir2-Feb-10 8:31

2-Feb-10 8:31

hi guyz...

-> i need some good articles or help regarding bluetooth programming in dotnet... i am also searching

the web but i am unable to find good one... plz help me out with this...

thanks...

take care...

J A Nasir K

Re: Bluetooth programming

Ennis Ray Lynch, Jr.2-Feb-10 8:35

Ennis Ray Lynch, Jr.

2-Feb-10 8:35

Bluetooth is basically writing to COM ports so any COM port tutorial will suit your needs, or should.

Need custom software developed? I do custom programming based primarily on MS tools with an emphasis on C# development and consulting.

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"Sir I exist!"
"However," replied the universe,
"The fact has not created in me
A sense of obligation."
--Stephen Crane

Re: Bluetooth programming

Giorgi Dalakishvili2-Feb-10 23:05

Giorgi Dalakishvili

2-Feb-10 23:05

You can use 32feet.NET[^] library for working with bluetooth.

Also, here is a sample application: Exploring OBEX Devices Connected via Bluetooth[^]

Giorgi Dalakishvili

#region signature
My Articles

Browsing xkcd in a windows 7 way[^]

#endregion

When To Use 'this' in C#

Matt U.2-Feb-10 8:15

Matt U.

2-Feb-10 8:15

So I have been reading through a lot of code lately. That is, code samples and articles and such on CodeProject and elsewhere. And at seemingly random times I notice a method or property is accessed with 'this.' before it. Is there really a rule to using it, or does it make for easy readability depending on the situation? I rarely ever use it and I would like to know if it's bad practice not to. Poke tongue | ;-P

Re: When To Use 'this' in C#

Abhinav S2-Feb-10 8:21

Abhinav S

2-Feb-10 8:21

The this keyword provides access to the current instance of a class.

Information on this here[^].

Me, I'm dishonest. And a dishonest man you can always trust to be dishonest.
Honestly. It's the honest ones you want to watch out for...

Re: When To Use 'this' in C#

OriginalGriff2-Feb-10 8:25

OriginalGriff

2-Feb-10 8:25

You only need to use it to ~~disambiguify~~ tell which variable you actually mean. I.e.

private string parameter;
private void Method(string parameter)
   {
   this.parameter = "Class scope variable";
   parameter = "Method scope variable";
   }

Or when you pass the current instance to a method:

private void Method(MyClass)
   {
   ...
   }
   
private void AnotherMethod()
   {
   Method(this);
   }

Using it unnecessarily just clutters the code and makes it harder to read IMO.

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Re: When To Use 'this' in C#

Matt U.2-Feb-10 10:55

Matt U.

2-Feb-10 10:55

Okay, that makes plenty of sense. Thanks everyone for you input! Big Grin | :-D

Re: When To Use 'this' in C#

Ennis Ray Lynch, Jr.2-Feb-10 8:25

Ennis Ray Lynch, Jr.

2-Feb-10 8:25

Unfortunately, this is a suggested requirement of FXCOP and it is a very poor programming practice. It is my opinion that the over-user of the this keyword came from ignorant programmers who did not know of the keyboard shortcut for intellisense (ctrl + space) these ignorant programmers then went on to define a standard because they wanted code to be "readable" thus it became a standard. It then made it into FXCOP which is a MS tool and then, because it is an MS tool other companies "architects" decided that if MS does it then it must be good. However, MS code rarely, if ever passed through the recommended FXCOP settings without warnings ... to make a long story short:

Don't use this unless you really need to. The only real good time to use the keyword is when calling a method from another object that required a reference to the calling object such as:

public class Foo{

    public Foo(){
        Bar bar = new Bar(this);
    }
}
public class Bar{
    public Bar(Foo foo){}
}

In all other cases where you would be tempted to use the keyword you have inappropriately named your local and member variables. Fix them.

Re: When To Use 'this' in C#

Kevin McFarlane2-Feb-10 10:32

Kevin McFarlane

2-Feb-10 10:32

A lot of MS's generated code uses this.xxx. I don't especially mind it but like you say it's not really necessary. It seems to be a hangover from Java where it appears to be the house style.

Kevin

Re: When To Use 'this' in C#

DaveyM692-Feb-10 12:28

DaveyM69

2-Feb-10 12:28

Kevin McFarlane wrote:
A lot of MS's generated code uses this.xxx

A FormX.Designer.cs is full of it. I guess the principles are:

1. In a container (such as a form) that holds many different objects, explicitly stating the object that you are using a method or property of is probably good practice and leaves no room for ambiguity.

2. It allows for parameters and fields to have the same name (much more likely to occur in auto generated code). If you always access the field with this then there will be no issues in this situation.

Personally, I only use it in my hand written code in case 2 and only where needed.

Dave

Tip: Passing values between objects using events (C#)
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Why are you using VB6? Do you hate yourself? (Christian Graus)

Re: When To Use 'this' in C#

Kevin McFarlane3-Feb-10 0:08

Kevin McFarlane

3-Feb-10 0:08

Those are good rules of thumb. Smile | :)

Kevin

Re: When To Use 'this' in C#

Mycroft Holmes2-Feb-10 12:08

Mycroft Holmes

2-Feb-10 12:08

I find I use this whenever I refer to a form object ie this.Close() but almost nowhere else, not even when referring to a control on the form, weird!

Still I hated using

Me

in VB whereas this in c# doesn't offend me nearly as much!

Never underestimate the power of human stupidity
RAH

Re: When To Use 'this' in C#

AspDotNetDev2-Feb-10 17:05

AspDotNetDev

2-Feb-10 17:05

Ennis Ray Lynch, Jr. wrote:
keyboard shortcut for intellisense (ctrl + space)

Thanks for the tip! How about this:

// Save keystrokes and confuse other developers.
private SomeType i{get{return this;}}

// Make use of this (aka Me, aka i).
public SomeMethod()
{
    i.Close();
}

$Shucks | :-\$ Poke tongue | ;-P

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Re: When To Use 'this' in C#

Luc Pattyn2-Feb-10 17:17

Luc Pattyn

2-Feb-10 17:17

aspdotnetdev wrote:
this (aka Me, aka i)

aka notThat

Smile | :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

I only read code that is properly formatted, adding PRE tags is the easiest way to obtain that.
[The QA section does it automatically now, I hope we soon get it on regular forums as well]

Re: When To Use 'this' in C#

PIEBALDconsult2-Feb-10 12:37

PIEBALDconsult

2-Feb-10 12:37

I use it to piss people off.

Help with Drawing Polygons

Raztor02-Feb-10 7:51

Raztor0

2-Feb-10 7:51

Hello once again. I just made a program to draw triangles in a way that makes a nice effect, here's a picture:

http://i276.photobucket.com/albums/kk2/Raztor0/Capture.jpg[^]

Now, the way I'm drawing this is I have an array of 80 points which I'm telling C# to draw with the DrawPolygon command. Can you see that line that goes through the middle of the triangles? That line is a line connecting the first and last point in the array, can I somehow prevent C# from connecting that last line? Is there a different command that lets me connect every point in sequence?

Thanks for your time Smile | :)

Re: Help with Drawing Polygons

Luc Pattyn2-Feb-10 8:18

Luc Pattyn

2-Feb-10 8:18

Hi,

a polygon[^] is a closed path by definition, and Graphics.DrawPolygon closes the path for you if you haven't done so yourself. That is all documented in MSDN. The class holds more drawing methods though.

Smile | :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

I only read code that is properly formatted, adding PRE tags is the easiest way to obtain that.
[The QA section does it automatically now, I hope we soon get it on regular forums as well]

Re: Help with Drawing Polygons

Raztor02-Feb-10 8:24

Raztor0

2-Feb-10 8:24

Thank you for the info, but is there a way to connect each point without saying Graphics.DrawLine(pen, point, point)? I will do that if I have to but I really don't want to Frown | :(

Re: Help with Drawing Polygons

Luc Pattyn2-Feb-10 8:26

Luc Pattyn

2-Feb-10 8:26

Raztor0 wrote:
is there a way to connect each point without ...

yes, and I already said that.
like always, it starts by reading the documentation.
I tend not to spoon feed lazy people.

Unsure | :~

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

I only read code that is properly formatted, adding PRE tags is the easiest way to obtain that.
[The QA section does it automatically now, I hope we soon get it on regular forums as well]

Re: Help with Drawing Polygons

Raztor02-Feb-10 8:30

Raztor0

2-Feb-10 8:30

Ah, alright. I didn't get that, I thought you were trying to say that DrawPolygon is explained there, which made me think that it's explaining what I already know. Thanks anyway, I'll go check it out.

Re: Help with Drawing Polygons

Raztor02-Feb-10 8:40

Raztor0

2-Feb-10 8:40

Okay so I found DrawLines, this is exactly what I need :P Thank you for your help once again Big Grin | :-D

TAPI Platform Invoking

saeidfarahi2-Feb-10 7:44

saeidfarahi

2-Feb-10 7:44

I want to write a program communicating a modem to send and receive special data(in format of string) to/from other modems.I have some questions:
1- For this program, should I use kdtele library or TAPI?
2- I couldn't find any complete user reference for kdtele! can anyone post me any link or other documentations?
3- After I couldn't work with kdtele, as I said why, I started searching about TAPI and realized there isn't any c# library for it and I have to use Platform Invokation to use tapi3.dll COM component, but here
's my question:
Do I need to PInvoke all c++ functions, messages, members and structs of tapi3.dll which are needed to write my program in c++ and then use the invoked class in c#? or does any one did this PInvoke job?!

Re: TAPI Platform Invoking

DaveyM692-Feb-10 7:49

DaveyM69

2-Feb-10 7:49

I've never worked with it but this google search[^] shows some promising results

Dave

Tip: Passing values between objects using events (C#)
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Why are you using VB6? Do you hate yourself? (Christian Graus)

How to add an attribute to a XML node

Petri Luoto2-Feb-10 6:24

Petri Luoto

2-Feb-10 6:24

Hi,

I have a problem, because I cannot find a method like xmlWriter.WriteAttributeString, which would add an attribute to a single node (see below the underlined node <instdamt> with an attribute Ccy="EUR").

The WriteAttributeString adds nicely an attribute to an element, like for example <Amt Ccy="EUR">, if I put it after xmlWriter.WriteStartElement("Amt"). But that is not the problem. I will get an exception if I put it after the xmlWriter.WriteElementString("InstdAmt", txtInstdAmt.Text).

So, what should I do to get the attribute added to a node, like the example below? It doesen't seem to be the most common need, so therefore I didn't find much from google either.

<PmtId>
  <EndToEndId>20090821-E000001</EndToEndId>
</PmtId>
<Amt>
  <InstdAmt Ccy="EUR">100.01</InstdAmt>
</Amt>
<CdtrAgt>
  <FinInstnId>

Thanks
Petri

Re: How to add an attribute to a XML node

Dan Mos2-Feb-10 7:06

Dan Mos

2-Feb-10 7:06

I don't know much about xmlWriter(DOM in general). Haven't used for any but the simplest things.

This functionnal XLINQ creation/construction sure does work:

XDocument yourDoc= 
		new XDocument(
            	new XDeclaration("1.0", "UTF-8", "yes"),
				      new XElement("Amt",
					   new XElement("InstdAmt","101.01")
 		                	   	new XAttribute("Ccy", "EUR")

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