Re: Big Problem with multicasting. - C# Discussion Boards

webdudeIA4-Jan-04 10:53

4-Jan-04 10:53

I'm building an application that connects to SQL Server. I'd like to allow the user to choose one of their defined ODBC connections.

Does .NET provide any classes to assist with determining the system/user defined DSN's?

Coding in the heartland

Re: List of ODBC DSN's

Nick Parker4-Jan-04 11:25

Nick Parker

4-Jan-04 11:25

Yes, the ODBC DSN's are stored with the Windows registry. They are located in "LocalMachine\ODBC\ODBC.INI\ODBC Data Sources" and "CurrentUser\Software\ODBC\ODBC.INI\ODBC Data Sources" keys. There are many articles here on CP that discuss working with the registry under .NET. Does that help?

- Nick Parker
My Blog

Re: List of ODBC DSN's

webdudeIA4-Jan-04 13:18

webdudeIA

4-Jan-04 13:18

Thanks Nick.

I'll take a look at those.

Ron

Coding in the heartland

Re: List of ODBC DSN's

Nick Parker4-Jan-04 16:52

Nick Parker

4-Jan-04 16:52

Ron, where are you at in Iowa, I am near Des Moines.

- Nick Parker
My Blog

Re: List of ODBC DSN's

cjengler5-Jan-04 2:25

cjengler

5-Jan-04 2:25

Clinton, IA here. Good to know there are some Iowans on here.

Big Problem with multicasting.

HAHAHA_NEXT4-Jan-04 10:48

HAHAHA_NEXT

4-Jan-04 10:48

I had a huge problem with multicast adresses.
I need to send a multicast packet to my local area network,with all its IPs so other computer will been able to estabilish a TCP/IP connection.
My computer has 3 local area connections(1 for internet, 1 for internal network, and 1 for god know what...), and when i send packets it *Randomly* chooses a local area connection and send data to it.

Is there a way i can choose the local area connection (in CSharp) or can i send my packets to All the connections at once.

Re: Big Problem with multicasting.

leppie4-Jan-04 11:12

leppie

4-Jan-04 11:12

Sounds like a routing problem rather. netsh | ipconfig

leppie ::AllocCPArticle("Zee blog");
Seen on my Campus BBS: Linux is free...coz no-one wants to pay for it.

Re: Big Problem with multicasting.

HAHAHA_NEXT4-Jan-04 16:13

HAHAHA_NEXT

4-Jan-04 16:13

It can't be a routing problem since there is no routers at all.

It is simply the stupic computer choose randomly to what connection (or nick card) it sends its data.
Ex: I have 2 nick cards. With 2 assigned adresses:
192.168.0.1
and
169.254.111.190

The i send my multicast packet, but i never know which one it will uses.
Since my internal network passes throught 192.168.0.1, it it uses the other nick card, i had just send my message god know where.
Thus i need a way to either send the message to both of them or to choose which one.

(Windows is simple for people who use it for internet word and emails, but it is a constant headache for experts Mad | :mad:

)

Re: Big Problem with multicasting.

Heath Stewart4-Jan-04 18:22

Heath Stewart

4-Jan-04 18:22

"routing" has to do with a route table, not necessarily a router (which is really just a hardware device with a programmable route table and is dedicated to routing packets). TCP is configured to route packets through a particular network interface card (NIC) depending on the destination address. Any computer with a TCP stack uses a route table.

-----BEGIN GEEK CODE BLOCK-----
Version: 3.21
GCS/G/MU d- s: a- C++++ UL@ P++(+++) L+(--) E--- W+++ N++ o+ K? w++++ O- M(+) V? PS-- PE Y++ PGP++ t++@ 5 X+++ R+@ tv+ b(-)>b++ DI++++ D+ G e++>+++ h---* r+++ y+++
-----END GEEK CODE BLOCK-----

Re: Big Problem with multicasting.

leppie5-Jan-04 6:24

leppie

5-Jan-04 6:24

try this:

D:\Documents and Settings\lepp>netstat -r

Route Table
===========================================================================
Interface List
0x1 ........................... MS TCP Loopback interface
0x2 ...00 50 56 c0 00 08 ...... VMware Virtual Ethernet Adapter for VMnet8
0x3 ...00 50 56 c0 00 01 ...... VMware Virtual Ethernet Adapter for VMnet1
0x10005 ...00 05 1c 05 9c 67 ...... Realtek RTL8139/810X Family PCI Fast Ethernet NIC
===========================================================================
===========================================================================
Active Routes:
Network Destination        Netmask          Gateway       Interface  Metric
          0.0.0.0          0.0.0.0      192.168.0.1     192.168.0.2       20
     62.47.38.202  255.255.255.255      192.168.0.1     192.168.0.2       20
        127.0.0.0        255.0.0.0        127.0.0.1       127.0.0.1       1
      192.168.0.0    255.255.255.0      192.168.0.2     192.168.0.2       20
      192.168.0.2  255.255.255.255        127.0.0.1       127.0.0.1       20
    192.168.0.255  255.255.255.255      192.168.0.2     192.168.0.2       20
    192.168.213.0    255.255.255.0    192.168.213.1   192.168.213.1       20
    192.168.213.1  255.255.255.255        127.0.0.1       127.0.0.1       20
  192.168.213.255  255.255.255.255    192.168.213.1   192.168.213.1       20
    192.168.225.0    255.255.255.0    192.168.225.1   192.168.225.1       20
    192.168.225.1  255.255.255.255        127.0.0.1       127.0.0.1       20
  192.168.225.255  255.255.255.255    192.168.225.1   192.168.225.1       20
    217.84.117.73  255.255.255.255      192.168.0.1     192.168.0.2       20
        224.0.0.0        240.0.0.0      192.168.0.2     192.168.0.2       20
        224.0.0.0        240.0.0.0    192.168.213.1   192.168.213.1       20
        224.0.0.0        240.0.0.0    192.168.225.1   192.168.225.1       20
  255.255.255.255  255.255.255.255      192.168.0.2     192.168.0.2       1
  255.255.255.255  255.255.255.255    192.168.213.1   192.168.213.1       1
  255.255.255.255  255.255.255.255    192.168.225.1   192.168.225.1       1
Default Gateway:       192.168.0.1
===========================================================================
Persistent Routes:
  None

You can clearly see that each route is properly mapped. Use route to modify.

leppie ::AllocCPArticle("Zee blog");
Seen on my Campus BBS: Linux is free...coz no-one wants to pay for it.

Re: Big Problem with multicasting.

HAHAHA_NEXT5-Jan-04 7:10

HAHAHA_NEXT

5-Jan-04 7:10

But this doesn solve my problem:

Here is the my route table (The good info only).
224.0.0.0 224.0.0.0 65.92.106.225 65.92.106.225 1
224.0.0.0 224.0.0.0 169.254.111.190 169.254.111.190 1
224.0.0.0 224.0.0.0 192.168.100.1 192.168.100.1 1

Currently it uses 169.254.111.190 to send my multicast packets to.

Now if i disable the 169.254.111.190 my routing table would be:
224.0.0.0 224.0.0.0 65.92.106.225 65.92.106.225 1
224.0.0.0 224.0.0.0 192.168.100.1 192.168.100.1 1

and it will send the ulticast packets to 65.92.106.255

IF i disable this lat one i will get:
224.0.0.0 224.0.0.0 192.168.100.1 192.168.100.1 1
and my data would be send to 192.168.100.1

Now if i connect the other 2 i will get
224.0.0.0 224.0.0.0 65.92.106.225 65.92.106.225 1
224.0.0.0 224.0.0.0 169.254.111.190 169.254.111.190 1
224.0.0.0 224.0.0.0 192.168.100.1 192.168.100.1 1

and the data would be sent to 192.168.100.1

Thus you se, depending on some strange criteria, i never know where my data would be send to ?
It can be any of these 3.
224.0.0.0 224.0.0.0 65.92.106.225 65.92.106.225 1
224.0.0.0 224.0.0.0 169.254.111.190 169.254.111.190 1
224.0.0.0 224.0.0.0 192.168.100.1 192.168.100.1 1

I can do like send the data to the first one, but it will create several problems like with Unreal Tournement when you try to play on LAN and can not login.

Thus does anybody know how can i change it using CSharp. (Without disabling all the stuff, to which i will probably not have access anyway in the real world).

Re: Big Problem with multicasting.

Alois Kraus8-Jan-04 7:40

Alois Kraus

8-Jan-04 7:40

Your net mask seems to be very odd. are you sure you want 224.0.0.0 as net mask for all your connections. Keep also in mind that the network metric is 1 for all your connections. This number is used to decide which connection to choose if several routes are possible the route with the least metric number will be used.

Re: Big Problem with multicasting.

HAHAHA_NEXT8-Jan-04 8:28

HAHAHA_NEXT

8-Jan-04 8:28

I only put 224.0.0.0 because it is the only one i care about( multicast mask). The full thing would be too big to display.

I am aware of metrics, but i don't want to modify them since the application i am making is a game and you dont wont a game scrapping all your network info Smile | :)

Finding out when a Item comes into the display area of a ListView

ne20004-Jan-04 10:41

ne2000

4-Jan-04 10:41

Heyho ppl,

I'm currently trying to figure on HOW I can get a event/test for if an Item in a ListView is beeing displayed on the screen? The thing is I want to display the information only when it's needed (that is, when the users sees it) to optimize speed in very large ListView's.

Any ideas, tips, anything would be most helpfull.

Cheers,
Henrik

Re: Finding out when a Item comes into the display area of a ListView

Heath Stewart4-Jan-04 18:19

Heath Stewart

4-Jan-04 18:19

The default implementation of the ListView class doesn't support virtual lists. Instead, you'll have to extend the ListView class with your own class and override WndProc to provide a lot of native concepts. Keep in mind that the ListView control is just a wrapper for the List View common control. There are ways you can do this, but you'll have to P/Invoke functions like SendMessage, create many differents structs, and define many enums or constants that reflect the values of all the Windows messages and notifications. See Windows Controls[^] in the MSDN Library for details. You should be familiar with Win32 APIs and programming.

You could also try searching CP or google the 'net for existing examples. It wouldn't surprise me if anyone has already done this.

String Width

Luther Baker4-Jan-04 10:38

Luther Baker

4-Jan-04 10:38

Is there a simple way to explicitly get the width of text in a control?

In general, I would like to dynamically size labels, buttons, listboxes, etc. depending on their contents.

I don't have to get the font, draw the text somewhere else and measure it do I?

Thanks,

-Luther

Re: String Width

ne20004-Jan-04 10:43

ne2000

4-Jan-04 10:43

I think you should check out Graphics.MeasureString

Cheers,
Henrik

Re: String Width

markdbd4-Jan-04 19:31

markdbd

4-Jan-04 19:31

Thanks I was also looking for this.

Re: String Width

Luther Baker6-Jan-04 18:27

Luther Baker

6-Jan-04 18:27

That looks like its worth a shot.

I guess, if text on a button spans 2 lines, I need to get the "size" of the button's print area.
That may be different than the size of the button right?

Maybe there is a "client area size" property or something ...

In any case, that call starts me off.

Thanks,

-Luther

Re: String Width

Luther Baker7-Jan-04 11:39

Luther Baker

7-Jan-04 11:39

Ok - I know this is a naive question, but where do I get a graphics object.

I am not in an event handler. I am in my custom control's constructor. Its not attached to anything. I just create a button and I've set the Text property, and now I want to set the Size property.

It seems that I can't create an instance of the graphics object ... and this is not a static method.

I'm not a GDI+ expert but I would guess that I can't just create a Graphics object because there is more to the drawing context that must be defined. Where am I drawing? Which window are we drawing to, etc. Maybe I can must measure the string size in the OnPaint handler (using the parameterized graphics object).

Thanks,

-Luther

ComboBox

Luther Baker4-Jan-04 9:46

Luther Baker

4-Jan-04 9:46

Is there a switch to disallow manual text entry into a ComboBox?

Or do I need to catch the KeyPress event and impl this myself?

-Luther

Re: ComboBox

Nick Parker4-Jan-04 10:06

Nick Parker

4-Jan-04 10:06

You need to set the ComboBoxStyle to DropDownList. Check ComboBoxStyle Enumeration[^] for further details.

- Nick Parker
My Blog

Re: ComboBox

Charlie Williams4-Jan-04 10:07

Charlie Williams

4-Jan-04 10:07

Set the control's DropDownStyle to DropDownList

Charlie

if(!curlies){ return; }

Re: ComboBox

Luther Baker4-Jan-04 10:39

Luther Baker

4-Jan-04 10:39

Thank you both.

-Luther

Custom Control

Luther Baker4-Jan-04 8:59

Luther Baker

4-Jan-04 8:59

I would like to make the following custom control.

A button, that opens a drop down list. Essentially, a combo box, but I don't want the appearance of a combo box. I want a button.

My initial problem is this. The drop down list may appear outside of its parent's bounds. Imagine a thin panel on the top of a form (like a toolbar) with this control attached to it. The control may have to draw the drop down list ON TOP OF the other controls immediately beneath the toolbar.

I'm used to something like css (position: absoloute). I guess the MainMenu does this. Do I need to custom draw the drop down list control?

Suggestions?

-Luther

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