C# Discussion Boards - CodeProject

Re: How to refresh a form

21-Jun-07 14:54

Hi Colin,

I'm sure nullable types have some value (no pun intended), otherwise they
would not have been added to C#.

So far whenever I was short of a special value (such as DateTime.MinValue),
I used a class rather than a struct so I could use null to indicate "has no value".

I still have to encounter the first case I really can take advantage of a
nullable value; maybe a long history without them made me develop patterns
that just walk around them ?

Regards,

Luc Pattyn

[My Articles] [Forum Guidelines]

Re: struct and const

PIEBALDconsult21-Jun-07 11:09

PIEBALDconsult

21-Jun-07 11:09

Same thing, but with nullable type -- still not recommended practice though.

public struct Point
{


private int? _x,_y;

public int
x
{
    get
    {
        if ( _x.HasValue )
        {
            return ( _x.Value ) ;
        }
        else
        {
            // throw something
        }
    }

    set
    {
        if ( !_x.HasValue )
        {
            _x = value ;
        }
        else
        {
            // throw something
        }
    }
}

public int
y
{
    get
    {
        if ( _y.HasValue )
        {
            return ( _y.Value ) ;
        }
        else
        {
            // throw something
        }
    }

    set
    {
        if ( !_y.HasValue )
        {
            _y = value ;
        }
        else
        {
            // throw something
        }
    }
}

How to refresh a form

kaushal65421-Jun-07 3:43

kaushal654

21-Jun-07 3:43

In my application I represent data stored in sql 2005 by "dundas" graphs. That data are dynamically updated. I want to refresh my graphs automatically.

Ylno21-Jun-07 14:30

Ylno

21-Jun-07 14:30

Hello,

I'm pretty new to all this so i hope i haven't picked up the wrong end of the stick..

If you want the form to re-paint it's self then you can use then following method :

.Invalidate()

That will cause the control to re-draw it's self.

how can we find a *.dmp in a directory in c#

cancerion21-Jun-07 3:40

cancerion

21-Jun-07 3:40

hello

can anyone help me

how can we find a *.dmp in a directory in c#???

thanks in advance

sachin

Re: how can we find a *.dmp in a directory in c#

Wjousts21-Jun-07 3:42

Wjousts

21-Jun-07 3:42

Directory.GetFiles(mypath,"*.dmp);

Re: how can we find a *.dmp in a directory in c#

Giorgi Dalakishvili21-Jun-07 4:00

Giorgi Dalakishvili

21-Jun-07 4:00

I guess you meant Directory.GetFiles(mypath,"*.dmp");

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Re: how can we find a *.dmp in a directory in c#

Wjousts21-Jun-07 6:54

Wjousts

21-Jun-07 6:54

how to add value and text in combo box in c# windows application

monuSaini21-Jun-07 2:45

Re: how to add value and text in combo box in c# windows application

21-Jun-07 2:45

Hello every body,

I want to add items in combo box (drop down style sets to DropdownList)

with text and values.

I am able to add only text not its value.

Please help,

Regards,

rahul saini

Luc Pattyn21-Jun-07 2:49

Re: how to add value and text in combo box in c# windows application

21-Jun-07 2:49

A combobox list only holds text strings; to map these onto values, you can
rely on the SelectedIndex property (unreliable, in case the list gets changed)
or use a HashTable; if the text is in some way a string representation of the value,
you could also parse the text.

Smile | :)

Luc Pattyn

[My Articles] [Forum Guidelines]

monuSaini21-Jun-07 2:54

Re: how to add value and text in combo box in c# windows application

21-Jun-07 2:54

Hello Luc Pattyn,

Thanks for your rply,

Can you help me out how to use hash table.

Regards,

rahul saini

Luc Pattyn21-Jun-07 2:59

Re: how to add value and text in combo box in c# windows application

21-Jun-07 2:59

HashTable ht=new HashTable();
ht.Add("one", 1);
ht.Add("two", 2);
...

string s=myCombo.Text;    // if "two"
int myValue=(int)ht[s];   // then 2

Luc Pattyn

[My Articles] [Forum Guidelines]

monuSaini21-Jun-07 3:04

Re: how to add value and text in combo box in c# windows application

21-Jun-07 3:04

Hello Luc,

Thanx.

Can you send me any link from where i can get detail knowlede of hash table with examples.

Regards,

rahul saini

Luc Pattyn21-Jun-07 3:26

Re: how to add value and text in combo box in c# windows application

21-Jun-07 3:26

Hi,

there is a little Search box higher up on this page; did you ever try it ?
there also is MSDN documentation.
There are thousands of books on programming in general and on C# specifically.
And finally there is Google.

Smile | :)

Luc Pattyn

[My Articles] [Forum Guidelines]

MrMahjong21-Jun-07 2:51

Re: how to add value and text in combo box in c# windows application

21-Jun-07 2:51

Hi!

Are you trying to specify its text? When activating the style DropDownList you have to set it by using the index of items existing in your combobox.

monuSaini21-Jun-07 2:57

Re: how to add value and text in combo box in c# windows application

21-Jun-07 2:57

Hello,

I just want to specify the text and value in combo box

Regards,

rahul saini

MrMahjong21-Jun-07 3:03

Re: how to add value and text in combo box in c# windows application

21-Jun-07 3:03

comboBox1.Items.Add("hello"); // new value

monuSaini21-Jun-07 3:10

Re: how to add value and text in combo box in c# windows application

21-Jun-07 3:10

Thnks for help,

But i want to add its value also

How to do that?

Regards,

rahul saini

Luc Pattyn21-Jun-07 3:30

Re: how to add value and text in combo box in c# windows application

21-Jun-07 3:30

a combobox holds and shows a list of strings, no more, no less.

Luc Pattyn

[My Articles] [Forum Guidelines]

Luc Pattyn21-Jun-07 4:27

Re: how to add value and text in combo box in c# windows application

21-Jun-07 4:27

Sorry, my previous message is wrong and Chintan.Desai is correct:
ComboBox can be loaded from a DataSource which can handle both a DisplayMember
and a ValueMember as the help on ListControl.DataSource explains.

Smile | :)

Luc Pattyn

[My Articles] [Forum Guidelines]

Chintan.Desai21-Jun-07 3:44

Chintan.Desai

21-Jun-07 3:44

Hey,
Try this link.As combo box gives property to assign the display string called as "Display member" and also help to stores its hidden values called as "Value Member" at each index.

ms-help://MS.VSCC.v80/MS.MSDN.v80/MS.NETDEVFX.v20.en/CPref17/html/P_System_Windows_Forms_ListControl_DisplayMember.htm#codeExampleToggle

nJoy. Rose | [Rose]

Regards
Chintan
www.visharadsoft.com
(Nothing is so purify as KNOWLEDGE)

Server/Client connection problem TCP

MrMahjong21-Jun-07 2:45

Re: Server/Client connection problem TCP [modified]

21-Jun-07 2:45

Hi guys! My first post here is ofcourse a little problem of mine! =) ive been looking pretty mutch everywhere, asking my proffesor and such, and we cant figure this out at all. I even analyzed the network trafic with Wireshark to see what was going on. No luck. So now im turning to you hardcore guys here at The Code Project Wink | ;)

Well to the problem. Im doing a really, REALLY simple chat client. (intending to control the mouse over ethernet). Where everything stops is when im trying to connect to the server.

On the client machine im running Vista using standard IPv6, and the Server im running XP Pro with IPv6. When launching the code below i can see from the network analyzing that it is actully sending packets and reciving to and from the server machine.

Then it gives me the most odd explenation ever.
"No connection could be made because the target machine activley refused it".

Ive tried to open up the network as mutch as possible to do a trial and error thing, but still no luck.

I dont even need to have my server app up and running. it still gives me the same message.

This is the Client code:

public void RunClient()
{
    try
    {
        Client = new TcpClient();
        Client.Connect("192.168.1.33", 50000);

        outputStream = Client.GetStream();

        Writer = new BinaryWriter(outputStream);

    }
        catch (Exception e) { MessageBox.Show(e.Message); }
    }
}

This is the servercode:

private void RunServer()
{
    TcpListener listener;
    
    try
    {
        IPAddress local = IPAddress.Parse("127.0.0.1");
        listener = new TcpListener(local, 50000);
                
        listener.Start();

        while (true)
        {
            Connection = listener.AcceptSocket();
            MessageBox.Show("Someone got connected."); ...

The servercode doesnt even reach the MessageBox.Show code. Seems like it is something external that is keeping the connection away. Anyone have any idea or could kick me in the right direction?

Thanks in advance for occupying your time =)

Luc Pattyn21-Jun-07 2:53

Re: Server/Client connection problem TCP

21-Jun-07 2:53

127.0.0.1 is localhost in IPv4; where is the IPv6 stuff ?

BTW dont show Exception.Message, show Exception.ToString() instead; it will show
much more information.

Smile | :)

-- modified at 9:01 Thursday 21st June, 2007

Luc Pattyn

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MrMahjong21-Jun-07 3:01