C# Discussion Boards - CodeProject

Rassul Yunussov29-Jun-05 19:13

29-Jun-05 19:13

What object has the behavior like a vector of STL?
I'd like to access the objects like this:
a[3], a[4], and i'd like to have a dinamic array, that can grow up...

Re: Collection

Christian Graus29-Jun-05 19:23

Christian Graus

29-Jun-05 19:23

ArrayList

Christian Graus - Microsoft MVP - C++

OleDbTransaction (rollback)

myNameIsRon29-Jun-05 19:12

myNameIsRon

29-Jun-05 19:12

Hi,
I'm new to programming and I can't find a sample of OleDb Transactions that can rollback BOTH ExecuteNonQuery() and myDataAdapter.Update all in one try/catch statement.
I found this link that shows the ExecuteNonQuery...
http://msdn2.microsoft.com/library/h8459s0c(en-us,vs.80).aspx
Is it possible to have both ExecuteNonQuery and DataAdapter.Update in the same rollback transaction?

thanks,
Ron

Trouble with marshalling structure

Josh Lindenmuth29-Jun-05 18:42

Josh Lindenmuth

29-Jun-05 18:42

Hello,

We are trying to marshal a simple C structure within our C# code. All values are coming across except for doubles (bolded below). A double comes across as junk. Any help you can provide would be appreciated.

Here is our C structure:

<br />
struct other_earn {<br />
   short o_id;<br />
   char o_desc[12];<br />
   char o_tpind[2];<br />
   char o_payee[31];<br />
   char o_addr1[31];<br />
   char o_addr2[31];<br />
   char o_addr3[31];<br />
   char o_hours[2];<br />
   double o_amt1;<br />
   short o_dept;<br />
   char o_txficas[2];<br />
   char o_txficam[2];<br />
   char o_txfit[2];<br />
   char o_txfuta[2];<br />
   char o_txsit[2];<br />
   char o_txsuta[2];<br />
   char o_txloc[2];<br />
   short o_mdt;<br />
   char o_wcexempt[2];<br />
}<br />

And here is how we marshal the struct. Note that all fields except the double are marshalled without issue. We have the same problem with all our other structs:

<br />
        [StructLayout(LayoutKind.Sequential)]<br />
        public struct ROtherEarn<br />
        {<br />
            public Int16 o_id;<br />
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 12)]<br />
            public String o_desc;<br />
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 2)]<br />
            public String o_tpind;<br />
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 31)]<br />
            public String o_payee;<br />
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 31)]<br />
            public String o_addr1;<br />
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 31)]<br />
            public String o_addr2;<br />
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 31)]<br />
            public String o_addr3;<br />
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 2)]<br />
            public String o_hours;<br />
            public Double o_amt1;<br />
            public Int16 o_dept;<br />
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 2)]<br />
            public String o_txficas;<br />
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 2)]<br />
            public String o_txficam;<br />
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 2)]<br />
            public String o_txfit;<br />
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 2)]<br />
            public String o_txfuta;<br />
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 2)]<br />
            public String o_txsit;<br />
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 2)]<br />
            public String o_txsuta;<br />
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 2)]<br />
            public String o_txloc;<br />
            public Int16 o_mdt;<br />
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 2)]<br />
            public String o_wcexempt;<br />
        }<br />

Thanks,
Josh Lindenmuth

Re: Trouble with marshalling structure

Bojan Rajkovic30-Jun-05 15:50

Bojan Rajkovic

30-Jun-05 15:50

What do you mean it's not being marshaled correctly?
As in it won't compile?
As in when you try to use the structure it behaves unexpectedly?

Did you try using the MasrhalAs(UnmanagedType.R4) or MarshalAs(UnmanagedType.R8) properties? As I recall, a C double is smaller than a C# double or something to that effect. (The reason I think this is because for some reason I think that a C long is actually 4 bytes while a C# long is 8 bytes)

So try adding a MarshalAs(UnmanagedType.R4) to your Double. (R4 and R8 marshal floating-point numbers, I2, I4, and I8 marshal integers)

function template

BicycleTheif29-Jun-05 17:55

BicycleTheif

29-Jun-05 17:55

Can i create a function template in c#.if so how to do it?

Nithya

Re: function template

Christian Graus29-Jun-05 18:12

Christian Graus

29-Jun-05 18:12

Only in VS.NET 2005, which is currently in beta 2.

Christian Graus - Microsoft MVP - C++

I have trouble with fgets function in C code

dinh van hai29-Jun-05 17:20

dinh van hai

29-Jun-05 17:20

Hi,

In C# code I declared like this:

[DllImport("mydll.dll")]
public static extern int SearchString(out double x);

And I called the function:
double m_vo2Max=1;
SearchString(out m_vo2Max);

The SearchString function is on the mydll.dll. This dll is written in VC++ and the description is here:

#include "stdafx.h"
#include <stdio.h>

BOOL APIENTRY DllMain( HANDLE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved
)
{
return TRUE;
}

int WINAPI SearchString (double &X)
{
FILE *F;
char szString[255];
F= fopen("C:\\ParaLimit1.tbf", "rt");
fgets(szString, 255, F);
fclose(F);
return 1;
}

I always have an error : System.NullReferenceException
Additional Information : Object reference not set to an instance of an object.

I checked and found out that the error in the code below:
fgets(szString, 255, F);
Can you help me to solve this error.

Thank you,

Re: I have trouble with fgets function in C code

Christian Graus29-Jun-05 18:14

Christian Graus

29-Jun-05 18:14

Why are you using C file handling instead of C++ ?

You should check if F is NULL, perhaps that's where the real problem is.

Christian Graus - Microsoft MVP - C++

Run another console application in my console application

eggie529-Jun-05 13:08

eggie5

29-Jun-05 13:08

I have a console application and let's say I have another console application (native c++ and I don't have the source) and I want to run that native application with my app like I would start it in cmd.exe.

For example, say my app was named ant.bat, to run it in the console I would type the C:\antroot\ant and it would run and display it's text in that console window.

Now I want to start ant.bat (Process.Start()???) and but have it run in my console window that my managed app is running in. Because if I just use Process.Start() it runs ant.bat in a new console window and closes when execution is complete.

Any ideas?

/\ |_ E X E GG

Re: Run another console application in my console application

Matt Gerrans29-Jun-05 14:37

Matt Gerrans

29-Jun-05 14:37

Try this:

public static void launch( string name, string workingDir )
{
    System.Diagnostics.Process process = new System.Diagnostics.Process();
    process.StartInfo.FileName = name;
    process.StartInfo.WorkingDirectory = workingDir;
    process.StartInfo.UseShellExecute = false;
    process.StartInfo.RedirectStandardOutput = true;
    process.StartInfo.RedirectStandardError = true;
    // (You could also do StarardInput if you need to.)
    process.Start();
    System.Console.Write(process.StandardOutput.ReadToEnd());
}

You could also throw in process.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;, but I don't think it's necessary.

By the way, this also answers the gcc question below.

Matt Gerrans

Re: Run another console application in my console application

eggie530-Jun-05 6:51

eggie5

30-Jun-05 6:51

Thanks that works just as I like.

I have another question though. If, for example, I wanted to set an environmental variable with my computer I would go like this in the command prompt....

//We'll set the location of java<br />
<br />
set JAVA_HOME=C:\jdk1.3.1_16 //then hit enter

How would I do this programmicly in C#?

Thank you for your time.

/\ |_ E X E GG

Re: Run another console application in my console application

leppie30-Jun-05 7:45

leppie

30-Jun-05 7:45

It's in the StartInfo, envorinmental variables. Poke tongue | ;-P

^{xacc-ide 0.0.15 now with C#, MSIL, C, XML, ASP.NET, Nemerle, MyXaml and HLSL coloring - Screenshots}

Re: Run another console application in my console application

Matt Gerrans30-Jun-05 7:55

Matt Gerrans

30-Jun-05 7:55

And to answer your next question: ProcessStartInfo Members[^] Big Grin | :-D

Matt Gerrans

FullRowSelect in DataGrid

Jassim Rahma29-Jun-05 11:52

Jassim Rahma

29-Jun-05 11:52

How can I FullRowSelect in DataGrid using C#?

Jassim Rahma

Re: FullRowSelect in DataGrid

Hugo Migneron30-Jun-05 3:09

Hugo Migneron

30-Jun-05 3:09

You can use DataGrid.CurrentRowIndex = index

Hugo Migneron

Header information in UDP Packet

Hugo Migneron29-Jun-05 9:36

Hugo Migneron

29-Jun-05 9:36

Hello,
I am using UDP protocol to broadcast a packet on the network. After I send this packet, some devices on the network answer with a UDP datagram packet containing some information.

My problem is that whenever one of these devices answer, (I know I get the packet because the Socket.Receive function returns me the data I am waiting for) I don't know who this packet is coming from. I am looking for a way to know the IP Address of the packet sender.

This is my code :

<br />
IPEndPoint Broadcast = new IPEndPoint(IP, 2000);<br />
EndPoint BroadcastEP = (EndPoint)Broadcast;<br />
<br />
socket = new Socket(System.Net.Sockets.AddressFamily.InterNetwork,<br />
	SocketType.Dgram, ProtocolType.Udp);<br />
socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 1);<br />
//msg is a byte[] that contains the data<br />
socket.SendTo(msg, 0, msg.Length, SocketFlags.None, BroadcastEP);<br />

Then, if I use the socket.Receive function, I get the payload of the packet but not the header information. Is there a way to get this information (Source's IP Address) with System.Net.Sockets or with System.Net.Sockets.UpdClient ?
I thought I could get this information by using socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.PacketInformation, ... but I just can't seem to figure out how to use it correctly.

If anyone knows how to do this, it would be greatly appreciated!

Hugo Migneron

running g++ using process.start

thepersonof29-Jun-05 8:31

thepersonof

29-Jun-05 8:31

Hi When I run g++ (to compile) using process.start I get the error: "g++.exe: Main.cpp: No such file or directory"

If I run g++ using the same arguments from command prompt it runs fine. whats going wrong?

cheers

Re: running g++ using process.start

Judah Gabriel Himango29-Jun-05 8:44

Judah Gabriel Himango

29-Jun-05 8:44

What is g++?

Tech, life, family, faith: Give me a visit.
I'm currently blogging about: Conversation With a Muslim
Judah Himango

Re: running g++ using process.start

S. Senthil Kumar29-Jun-05 9:02

S. Senthil Kumar

29-Jun-05 9:02

g++ is the gcc compiler for C++.

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

Re: running g++ using process.start

S. Senthil Kumar29-Jun-05 9:01

S. Senthil Kumar

29-Jun-05 9:01

You need to specify the full path of the Main.cpp file when you run it using Process.Start, or, you need to set the current directory to the directory where Main.cpp resides before starting the process.

This is because a process spawned using Process.Start by default, has its current directory set to the application directory of the parent process.

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

Re: running g++ using process.start

thepersonof29-Jun-05 9:54

thepersonof

29-Jun-05 9:54

Thanks a lot! How can I "set the current directory to the directory where Main.cpp resides before starting the process"

Cheers again

Re: running g++ using process.start

S. Senthil Kumar29-Jun-05 11:45

S. Senthil Kumar

29-Jun-05 11:45

You can use the ProcessStartInfo's WorkingDirectory property.

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

Re: running g++ using process.start

Matt Gerrans29-Jun-05 14:41

Matt Gerrans

29-Jun-05 14:41

I don't think changing the current directory is generally a good practice as it can cause all kinds of confusion. It is probably better just to set the StartInfo.WorkingDirectory property of the process instead. See http://www.codeproject.com/script/comments/forums.asp?forumid=1649&select=1150143&df=100&msg=1150143[^] for more details.

Matt Gerrans

Re: running g++ using process.start

Matt Gerrans29-Jun-05 14:42

Matt Gerrans

29-Jun-05 14:42

Oops, sorry Senthil, I didn't see your reply to yourself where you already pointed this out!

Matt Gerrans

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