Re: COM port problem - C# Discussion Boards

31-Oct-09 1:25

~~How to use COM port in C#[^]~~
Sorry - didn't understand your question properly. My bad.

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modified on Saturday, October 31, 2009 7:44 AM

OriginalGriff31-Oct-09 1:44

31-Oct-09 1:44

Having read the Stancrm post, I see what you are trying to do. If you connect two external machines to a single RS232 port, it may work. RS232 is intended for point to point work, not multidrop and its electrical specification is designed for just that. Certainly, the two devices will be able to hear anything you transmit on the port, (at least until the distances from the source port get too big) but it is unlikely that transmissions into the port from one of two connected devices will work - it may, but it will depend on the design of the hardware connected to the port and the physical tollerances of the components. (i.e. it may work with these two devices, but if one of them is changed for an identical model it may not, or it may work but only intermittently).

I would really consider why you are doing this, and look at better technology for it, such as RS485 or USB.

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Reza Shojaee31-Oct-09 2:05

Reza Shojaee

31-Oct-09 2:05

About possibility or no, I saw this configuration physically & with delphi software.
About using USB or RS485, My devices work with RS232.

Best Regards,
Reza Shojaee

OriginalGriff31-Oct-09 2:47

31-Oct-09 2:47

You can buy RS232 - RS485 converters from about £5 - don't know how good they are.
Similarly RS232 - USB converters, but they are more expensive.

Either solution would work better and be more reliable than multidrop RS232.

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idan_bismut1-Nov-09 9:54

How to send/recieve objects with sockets?

1-Nov-09 9:54

You'll need hardware that can allow to use pre-defined pin(s) as RX/TX.
For most standard uart hardware cards, the UART COM is usings pins #2/#3 (for RS-232). The other pins are used for RS-422/485 & handshake (RTS/CTS etc.) purpose.

If you have any FPGA & VHDL knowledge, you could code yourself some generic UART module that can handle 2 rs-232 on different pins assignments. and then use it as "middle-box" to communicate via it.
Could be some1 made such product already...

Chesnokov Yuriy31-Oct-09 0:19

Chesnokov Yuriy

31-Oct-09 0:19

What is the mechanism of converting objects to bytes seqs and recovering them back to send with sockets.

e.g. I need to send some structure over TcpClient and recieve it with TcpListener then send back some more data: strings, structures.

Is serialization used or some other specific approach that works with sockets?

Чесноков

Message Closed

31-Oct-09 0:52

stancrm

31-Oct-09 0:52

Message Closed

modified 23-Nov-14 7:24am.

Re: How to send/recieve objects with sockets?

Chesnokov Yuriy31-Oct-09 4:41

Chesnokov Yuriy

31-Oct-09 4:41

but serialization uses assembly specific data.
how to do it if the client and server is in different assemblies? but the structure is exactly the same?

I do not want to encode specific assembly to be used as reference in both client and server, that will serialize/deserialize the data.

Чесноков

Re: How to send/recieve objects with sockets?

harold aptroot31-Oct-09 5:20

harold aptroot

31-Oct-09 5:20

You could do it by hand

Re: How to send/recieve objects with sockets?

Chesnokov Yuriy31-Oct-09 8:55

Chesnokov Yuriy

31-Oct-09 8:55

what is that??? OMG | :OMG:

Чесноков

Giving range to Run time end and start date parameter

haleemasher30-Oct-09 23:53

haleemasher

30-Oct-09 23:53

Hi all, crystal reports are new for me. i need help for creating a report having two parameter which takes Start Date and End Date which contain the range of dates and when i select dates it show related reports.i want to fix date ranges at run time using C# code.
I take a code from an article but it doesn't work.
If u have any article plz give me link i will consult it.
advance thnx 4 help

Using Connectionstring

haleemasher30-Oct-09 23:52

haleemasher

30-Oct-09 23:52

i code a connection string in web.config in appsetting now i want to use that connection in dropdownlist which i want to bind through wizard. How i give that connection using wizard to bind it???

Re: Using Connectionstring

OriginalGriff31-Oct-09 0:46

Re: Using Connectionstring

31-Oct-09 0:46

Try the ASP.NET forum

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Keith Barrow31-Oct-09 3:03

Keith Barrow

31-Oct-09 3:03

This should really be posted in the asp.net forum, bur the process is the same as for winforms.
First, move the connection strings from the AppSettings into the specialised connectionStrings section(you'll have to google for this as I'm replying from my phone). This has a few advantages, first you can get a Connectionstring object, the connection strings can be encrypted in config separately and (most important in your case) the connection strings are now separate from the other app config.

Now all you need to do is iterate over the set of connection string and add the names to the dropdown list. Note that sending the strings themselves down to the client is a security risk. Once the client has responded with a selected name you can use it to look up the string from the config.

CCC solved so far: 2 (including a Hard One!)

How to access mdi parent's menustrip items from a child form [modified]

idan_bismut30-Oct-09 21:58

Re: How to access mdi parent's menustrip items from a child form

30-Oct-09 21:58

I have been trying to figure something for last couple of hours, but i'm unable to solve it & need some help.

I have project with 2 forms:
Form1 - MDI container
child_form1 - parent set to Form1

on menu_form i have MenuStrip called "MenuStrip1" and item called "item1".

on the item1 i have following code:

private void item1_Click(object sender, EventArgs e)
        {
            child_form1 cf1 = new child_form1();
            cf1.MdiParent = this;
            cf1.Show();
        }

now, for problem, i want to be able to modify Form1 menustrip items from the child menu. (specifically i want to uncheck the item1 when form is closed, but for the argument sake i just need to get proper handle/pointer to menu item).

So i've tried doing something like this:

Form main_form = this.MdiParent;
main_form.Controls["menustrip1"].Controls["item1"].Checked = false;

but it seems i can only get pointer/handle to the menustrip as a whole, but not to the item itself.
main_form.Controls["item1"] is not valid pointer
main_form.Controls["menustrip1"].Items does not exists

Am i missing something ??
How do i get handle to form's menustrip item(s) from another child form ?

Would appreciate any help in resolving the issue...

EDIT:
i managed to solve the problem myself, leaving msg as it might help others with same problem.

modified on Saturday, October 31, 2009 4:38 AM

idan_bismut30-Oct-09 22:37

Re: How to access mdi parent's menustrip items from a child form

30-Oct-09 22:37

I found the problem.
The modifiers of the menu item were set to "private", so child form could not "see" it.
Now i've changed to "Public" and this code allow to access it:

Form1 main_form = this.MdiParent as Form1;
main_form.item1.checked = false;

OriginalGriff30-Oct-09 23:37

Re: How to access mdi parent's menustrip items from a child form

30-Oct-09 23:37

THat is not a good idea - it works, but it is considered bad practice. Why? Because it locks the child form to the design of the parent form. You cannot now change the design of the parent form unless you check that this will have no effect on the child form.

The recommended way to do this is to generate an event in the child form which is subscribed to and handled by the parent form. The parent form then takes the action depending on what controls it is using.

To do this:
In the child form:

public partial class frmChild : Form
   {
   // Signal file change happened
   public event EventHandler Changed;

   protected virtual void OnChanged(EventArgs e)
      {
      EventHandler eh = Changed;
      if (eh != null)
         {
         eh(this, e);
         }
      }

   private void DoSomethingToChangeData()
      {
      OnChanged(null);
      }
   }

----- The assign to eh is in case the handler changes between null check and exec. (Unlikely, but possible)

----- The null check is to ensure there is a handler. If not, better to ignore it gracefully, than to rely on the thrown exception (NullReferenceException)

In the Parent form:

public frmParent()
    {
    frmChild.Change += new frmChange.ChangeHandler(Changed);
    }

//
// Fired when the file is changed at a lower level.
//
private void Changed(object sender, EventArgs e)
    {
    }

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idan_bismut31-Oct-09 3:47