Re: Class properties - C# Discussion Boards

S. Senthil Kumar3-Jul-05 22:05

3-Jul-05 22:05

You don't need to do anything, when the object has no live references to it, the GC (Garbage Collector) will automatically clean it up.

Regards
Senthil
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Re: How to release memory in c#

Matt Gerrans3-Jul-05 22:44

Matt Gerrans

3-Jul-05 22:44

Let's see the code. Then the replies can be more to the point.

On Disposable objects you can use the [b]using[/b] keyword.

Are you trying to solve a real problem (performance, memory?), or is this just latent anal-retentiveness of a recovering c/c++ programmer? Wink | ;)

Matt Gerrans

Main calendar in Outlook

kloakenratte3-Jul-05 20:56

kloakenratte

3-Jul-05 20:56

In Outlook it's able to create a lot of calendars... So, if my program writes a date in de calendar, it writes the date in the main calendar. How can I write my date in one of the other calendars?

Thanks for your help!

Eventhandling in Outlook

kloakenratte3-Jul-05 20:51

kloakenratte

3-Jul-05 20:51

Hi!

Can you explain to me how I can handle events in Outlook? I have no idea...
I want to catch calendar-events. So, if somebody deletes or writes dates, I want to know which date the user has deleted or written.
I couldn't find any examples...

Thanks for your help!

Re: Eventhandling in Outlook

S. Senthil Kumar3-Jul-05 21:03

S. Senthil Kumar

3-Jul-05 21:03

Did you try searching for "Outlook Automation"? Maybe you'd get a few pointers there.

Regards
Senthil
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Class properties

1nsp1r3d3-Jul-05 20:21

1nsp1r3d

3-Jul-05 20:21

Hi all,
While reading this tutorial, I encountered this:

<br />
class SplashScreen : System.Windows.Forms.Form<br />
{<br />
...<br />
    static SplashScreen ms_frmSplash = null;<br />
...<br />
}<br />

And I'm a bit worried because of this statement. How can a class have a property of itself? Or the static keyword makes it not act as a class property? Thanks.

Re: Class properties

S. Senthil Kumar3-Jul-05 21:02

S. Senthil Kumar

3-Jul-05 21:02

ms_frmSplash is a *reference* to a SplashScreen object, not a SplashScreen object itself. If you had a SplashScreen object itself, then it would be a problem, the compiler wouldn't be able to generate the object layout without going into infinite recursion. References are of a fixed size (regardless of the referenced object), so the compiler has no problem with the above code. The static keyword has nothing to do with that.

The code that you posted is very similar to something like this in C++

class Node
{
   Node *p;
};

Regards
Senthil
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Re: Class properties

Colin Angus Mackay3-Jul-05 21:06

Colin Angus Mackay

3-Jul-05 21:06

First, to correct the words that you are using, this is not a property, it is called a field in .NET (although many ex-C++ developers will call it a member variable).

1nsp1r3d wrote:
How can a class have a property of itself?

A class can have "fields" of any type. Including itself. As to how? Well, the code snipped you gave shows you how.

1nsp1r3d wrote:
Or the static keyword makes it not act as a class property?

The static keyword makes the "field" available at the class level rather than at the object instance level.

A better question would have been "why did they do this?"

If you are creating a "singleton" (that is a class that only ever has one instance through the lift of the application) then you need to create a static reference to the one and only instance of the class in the class.

If an object is part of a chain of object then it will need to reference another object of the same type. For example, the "decarator pattern" does this.

Does this help?

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Re: Class properties

1nsp1r3d3-Jul-05 21:12

1nsp1r3d

3-Jul-05 21:12

Thanks go to both of you Smile | :)

And Another One question

Rassul Yunussov3-Jul-05 19:20

Rassul Yunussov

3-Jul-05 19:20

About optimisation...
I usend the CMemFile in C++ to read full file into the memory, and then worked with the memory like with file...
I would like to use this way here... So, how to read the file into the memory and then create BinaryReader to this block of memory... I think there must be some method to convert from byte array to ByteStream....
Please Help...

Re: And Another One question

S. Senthil Kumar3-Jul-05 19:37

S. Senthil Kumar

3-Jul-05 19:37

You're looking for the

System.IO.MemoryStream class. 

Regards
Senthil
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Paging in Datagrid

skrishnasarma3-Jul-05 19:06

skrishnasarma

3-Jul-05 19:06

I wiold like to do paging say by 1 , 2, 3 or next/Previous in datagrid (In Win form application)
Any Input or Sample code please?

Re: Paging in Datagrid

WillemM4-Jul-05 0:12

WillemM

4-Jul-05 0:12

It would ask a lot of work, but you can do the following:

Create two datasets, one dataset has all the data, the second one only has the records to view (one page at a time).

page = 30 records (begins at 0)

beginrecord = page * 30
endrecord = (page * 30) + 30

Every time you go to the next or previous page execute the following procedure for the new page (clear the view dataset first):

//This code is an example probably doesnt work this way
string configuredTable = "MyTable";
DataSet myDataSet = new DataSet();

for(int index = beginrecord; index < endrecord; index++) 
{
  DataRow newrow = viewdataset.Tables[configuredTable].NewRow();

  //TODO: Setup the data in the viewrow

  viewdataset.Tables[configuredTable].AddRow(newrow);
}

viewdataset.AcceptChanges();

walk through the dataset table with the records you want to display and add them to a separate dataset. (Don't forget to call AcceptChanges())

There's one problem though: You should not edit the records in the view dataset, because that one gets cleared every time you change the page. Ofcourse you can implement the DataRowAdded eventhandler and add the same data to the non-view dataset.

WM.

What about weapons of mass-construction?

BigEndian Format

Rassul Yunussov3-Jul-05 19:04

Rassul Yunussov

3-Jul-05 19:04

HellO!
Who knows ESRI Shape file format, will understand my problem...
I got a shape file, where some integers are in little endian format and other are in big endian format... So, my question is - how to convert this two formatsa between each other? For example i have an integer a in BigEndian format, i'd like to see it in Little Indian format... Thaks...

Re: BigEndian Format

S. Senthil Kumar3-Jul-05 19:18

S. Senthil Kumar

3-Jul-05 19:18

Converting from big endian to littel endian is just a matter of reversing the bytes, isn't it? You can do that easily with code like this.

int ReverseBytes(int original)
{
  int reversed = 0;
  for (int i = 0; i<4; i++)
  {
    reversed |= (byte)(original & 0x000000FF);
    reversed << 8;
    original >> 8;
  }

  return reversed;
}

Regards
Senthil
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Re: BigEndian Format

Kri53-Jul-05 22:17

Kri5

3-Jul-05 22:17

Small correction...if you loop 4 times you drop bytes off the right hand side of the reversed integer, so it should be like this (note also use of unsigned):

<br />
<br />
   unsigned int reversed = 0;<br />
<br />
   for (int i = 0; i<3; i++)   // loop 3 times...<br />
   {<br />
      reversed |= (BYTE)(original & 0x000000FF);<br />
      reversed = reversed << 8;<br />
      original = original >> 8;<br />
   }<br />
<br />
<br />
   // ...and then just place last byte on left-hand side of resulting integer<br />
   reversed |= (BYTE)(original & 0x000000FF);<br />

Re: BigEndian Format

S. Senthil Kumar3-Jul-05 23:42

S. Senthil Kumar

3-Jul-05 23:42

Yeah, you were right, there was an off by one error. Here's the right code.

int reversed = 0;
for (int i = 0; i<4; i++)
{
	reversed <<= 8;
	reversed |= (byte)(original & 0x000000FF);
	Console.WriteLine("{0:x}", reversed);
	original >>= 8;
}

Regards
Senthil
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Re: BigEndian Format

S. Senthil Kumar3-Jul-05 23:40

S. Senthil Kumar

3-Jul-05 23:40

Apologies, my previous post had a small bug which caused an extra left shift to occur. Here's the correct code

int reversed = 0;
for (int i = 0; i<4; i++)
{
	reversed <<= 8;
	reversed |= (byte)(original & 0x000000FF);
	original >>= 8;
}

Regards
Senthil
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networking ?

Anonymous3-Jul-05 17:05

Anonymous

3-Jul-05 17:05

what is the best way to have a client wait for a response from the server? like a login system where the client sends the login info to the server and while the server checks the login info in a database the clients main thread holds till the read thread get a response from the server like good login or bad login.

Re: networking ?

Yulianto.3-Jul-05 18:32

Yulianto.

3-Jul-05 18:32

Anonymous wrote:
what is the best way to have a client wait for a response from the server?

Busy mouse pointer?

<italic>Work hard, Work effectively.

Outlook express add in

Wessam Fathi3-Jul-05 14:15

Wessam Fathi

3-Jul-05 14:15

I'm trying to develop an add-in for Outlook Express, the add-in is supposed to intercept sending mails and (optionally) add attachments to the mail being sent.

I have already done that on Microsoft Outlook using Visual Studio Tools for Office, but I couldn't find any way to do it on Outlook Express.

Help would be greatly appreciated, just point me on the way.

Thanks in advance,

Wessam Fathi

Wessam Fathi

Re: Outlook express add in

Carsten Zeumer3-Jul-05 22:16

Carsten Zeumer

3-Jul-05 22:16

As far is i know there is no extension API for Outlook Express.
The only way i could think of doing this is to have a Proxy SMTP-Server handling all outgoing mails.

/cadi

24 hours is not enough

Free resources

Libor Tinka3-Jul-05 13:15

Libor Tinka

3-Jul-05 13:15

Is there a simple way how to determine, if there's enough memory for a new object, if I know its size?

For example, I have an imaging app and user (ape) wants to resize image to 34676x80900 pixels. It's too much for his machine, but app will try to create a huge bitmap this way:

<br />
try {<br />
  <br />
  bmp = new Bitmap(userSize.Width, userSize.Height);<br />
} catch () {<br />
<br />
  // Oops - probably not enough memory<br />
}<br />

My real application works with many Image objects and only dummy proofing are try-catch blocks, which are not preventing exceptions and are very slow.

Re: Free resources

Dave Kreskowiak3-Jul-05 16:21

Dave Kreskowiak

3-Jul-05 16:21

No, there isn't. You can only rough-guess if you've got enough free memory. Because if you have the amount you need, there's no way to tell that if, in that moment, it's all continguous.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

C# and ASP.NET

valvet3-Jul-05 12:59

valvet

3-Jul-05 12:59

Hey.. I'm very new to this but I'll try explaining the best I can.

Say I have a function in a "class library" project which gets imported by my "ASP.NET Web Application".

Now in my ASP.NET project I got:

private void Button1_Click(object sender, System.EventArgs e)
{
TestClass test = new TestClass();

test.TestFunction();
}

and my TestFunction looks like this:

public void TestFunction()
{
Console.WriteLine( "testing.." );
}

How would I go about writing the output of my TestFunction() to the actual page in my ASP.NET project? Do I need to set the message from TestFunction() to a public string and then use that string to display what I need on the web page?

Another example..

public void TestFunction()
{
try
{
Console.WriteLine( "testing.." );
}
catch( Exception E )
{
Console.WriteLine( "Ex: {0}", E.Message );
}
}

if TestFunction() should error now, it'll print out the Exception message to the console.. but I need it to print to the web page instead. I guess setting a string to the text now is not going to work.

Hope you understand and thanks for the help!

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