|
I know there are so many question regarding this NullReferenceException...
but still i couldn't find any solution for my prob...
i've got a runtime error...
it says that...
"An unhandled exception of type 'System.NullReferenceException' occurred in OraGraphing.exe
Additional information: Object reference not set to an instance of an object."
this is my code... the error is at price...
<br />
public int counter;<br />
public sting[] price;<br />
<br />
private void Form1_Load(object sender, System.EventArgs e)<br />
{<br />
OracleConnection oraConn = new OracleConnection("Data Source=quotes; user id=me; password=you;");<br />
OracleCommand oraCmd = new OracleCommand("SELECT isin, to_char(trading_date,'dd/mm/yy hh24:mi:ss'), last_done_price FROM realtime_tracking",oraConn);<br />
oraConn.Open();<br />
OracleDataReader oraDR = oraCmd.ExecuteReader();<br />
<br />
counter = 0;<br />
while(oraDR.Read())<br />
{ <br />
try<br />
{<br />
price[counter] = oraDR["last_done_price"].ToString();
}<br />
catch (NullReferenceException nre)<br />
{<br />
MessageBox.Show(nre.Message);<br />
}<br />
counter++;<br />
};<br />
<br />
oraDR.Close();<br />
oraConn.Close();<br />
}<br />
I think that error because of i didnt declare how large the array is... but how? since i didnt know how large is the data inside that database...
-----------------------------------------------
=^_^= I'm a noob whose trying to learn... =^_^=
|
|
|
|
|
|
yup..
its true.. when i put how many elements.. it runs correctly..
but.. i want to make it dynamically,
since the data in the database keeps updating/increasing/decreasing..
so.. basically i dont know the number of elements..
------------------------------------------------------
=^_^= Thank you to those who answer my question =^_^=
|
|
|
|
|
|
|
Use a list instead of an array, like an ArrayList, then you don't have to know the number of items to create it.
---
b { font-weight: normal; }
|
|
|
|
|
<br />
price = new string[oraDR.Count]; <br />
while(oraDR.Read())<br />
{ <br />
try<br />
{<br />
price[counter] = oraDR["last_done_price"].ToString();
}<br />
catch (NullReferenceException nre)<br />
{<br />
MessageBox.Show(nre.Message);<br />
}<br />
No hurries, no worries.
|
|
|
|
|
sorry 'bout themany replies, CP was working against me 
No hurries, no worries.
|
|
|
|
|
I want to Enumerate Users on Remote Machine with username and password. I am using NetEnumUser function in (Advapi32.dll)/ this function enumerates user with windows 2000 but when runs on windows xp it returns access denied. I am searching for a function that will authenticate my credentials and get the remote machine users.
Thanks in Advance
|
|
|
|
|
hello friends,
i am developing an application, which needs to transfer the data from one computer to another with the help of socket programming.
i want to make the server in the listening mode on port 80, so that whenever client send the connection request, it will be connected on port 80.
please tell me whether it is possible or not to put the application on the listening mode on port 80.
i tried it using system.net namespaces's SocketObj.Bind method using port 80 but it gives the error that
"Only one usage of each socket address (protocol/network address/port) is normally permitted".
this will work fine for other ports. but for other ports i have the problem that may be that port will be blocked by the company where this project is implemented.
please help me anyway if u can!
Thanks to all and codeproject too.
Gagan Deep Singla
Chandigarh - INDIA
|
|
|
|
|
Hi!
The error message you get is correct. A port can be assigned to a single application only.
In your case, a webserver will be listening on port 80 (because this is the regular port for web requests) when your application starts.
Either choose a different port (those above 1024 are usually not occupied by OS components, but may be used by other applications, so you better check a port list) or stop the web server to be able to use port 80.
Regards,
mav
|
|
|
|
|
dear mav,
thanx for replying so fast.
i can't disable the web server yaar. i have to use the 80 port while enable the web server.
if i will select other port than 80 then what about the security of that port. suppose i select the port 10800 then if firewall has disabled this port then user has to enable it.
because of this there can be chance of hacking too. because anybody can get in with the help of that port which is enabled.
please tell me what should i say to my seniors regarding this problem.
they dont want to open the special port for the application.
ok, tell me one thing if u can that how much chance of hacking is there, if any port is opened by any company. because on 80 port there is no chance of hacking.
please give me some solution for this.
thanx again for replying.
Gagan Deep Singla
Chandigarh - INDIA
|
|
|
|
|
Gagan Deep Singla wrote:
ok, tell me one thing if u can that how much chance of hacking is there, if any port is opened by any company. because on 80 port there is no chance of hacking.
Why can’t port 80 be hacked like any other port? Most web servers have been written with security in mind. When you create your server you’re going to need to put the same thought in to security as everyone else. There are no shortcuts here.
So use another port, if your customers really want this app they will open that port for your application. Just do your home work about what’s needed to keep your data safe.
-------------------------------
DEBUGGING : Removing the needles from the haystack.
|
|
|
|
|
thanx sir,
thanx for giving me response.
now i am using some other port like 10800.
thanx a lot.
bye
Gagan Deep Singla
Chandigarh - INDIA
|
|
|
|
|
Rehi!
I guess you're not really familiar with what's neccessary to "hack a port" (and neither are your seniors it seems...)
A port is just a communication facility, regardless of its port number.
A port itself cannot be "hacked", it's the application that's listening on that port that can be hacked, for example by sending especially prepared malicious network packets over this port. The application receives the packets and freaks out, performing actions it's not designed to do.
When your webserver is running on port 80, it can be hacked as easily or as hard as it can be hacked when it's running on port 8080.
When your application wants to communicate via a certain port, this port has to be accessable from outside and a firewall has to allow access to this port, but this doesn't mean whatever is running over this port is secure. It just means that the firewall is trusting your application not to perform malicious tasks that can be controlled or triggered by receiving network traffic via the open port.
Hope this cleared things up a bit.
Regards,
mav
|
|
|
|
|
thanx sir,
thanx for giving me response.
now i am using some other port like 10800.
thanx a lot.
bye
Gagan Deep Singla
Chandigarh - INDIA
|
|
|
|
|
Gagan Deep Singla wrote:
ok, tell me one thing if u can that how much chance of hacking is there, if any port is opened by any company. because on 80 port there is no chance of hacking.
That is totally incorrect. I do security demonstrations that include a live demo of a hack attempt on a badly written application* that runs on port 80. It amazes the audience that in only 2 minutes I can have the application that was supposed to be a simple ecommerce thing displaying the contents of the hard disk rather than the inventory of items for sale. Port 80 can be hacked just like any other port. As others have said, it is your responsiblity that the application you write is secure, whether it is running through your web server or whether you are creating sockets directly for it.
* I should note that I wrote the application for the purposes of this demonstration - It is illegal to hack into another person's application without permission. My security presentations always open with two slide summarising the relevant sections of the 1990 Misuse of Computers Act
My: Blog | Photos
WDevs.com - Open Source Code Hosting, Blogs, FTP, Mail and More
|
|
|
|
|
thanx sir,
thanx for giving me response.
now i am using some other port like 10800.
thanx a lot.
bye
Gagan Deep Singla
Chandigarh - INDIA
|
|
|
|
|
I have downloaded a .net control( tabPage ) as dll file but trial version;
Then i found a crack for it that generates a key for software.
But i dont know where apply this generated key??????????
|
|
|
|
|
What you do is call the people who wrote it, people who are trying to make a living writing software, people with families to feed and mortgages to pay, and you say 'I want to let you know that I am a scumbag, but because I tried to steal from you, you can have the keys to my car'.
Then slam your head in a door over and over until you wake up to yourself.
Christian Graus - Microsoft MVP - C++
|
|
|
|
|
Christian Graus wrote:
Then slam your head in a door over and over until you wake up to yourself.
My Five! 
-------------------------------
DEBUGGING : Removing the needles from the haystack.
|
|
|
|
|
|
Wow!! This must be one of the best questions ever! 
Go to their web page, click on the "Buy Now" link and after providing your credit card number, you'll get instructions on how to apply the key.
-- LuisR
Luis Alonso Ramos
Intelectix - Chihuahua, Mexico
Not much here: My CP Blog!
The amount of sleep the average person needs is five more minutes. -- Vikram A Punathambekar, Aug. 11, 2005
|
|
|
|
|
Yeah, what a moron. I love that he stole the key, but is too stupid to work out what to do with it...
BTW, I'm still in linker hell, I'd appreciate your comments to my post in the C++ forum. I'm thinking that the DICOM library may be linking to the old string.h, etc, headers, but I'm really not sure what is going on....
Christian Graus - Microsoft MVP - C++
|
|
|
|
|
Christian Graus wrote:
I'd appreciate your comments to my post in the C++ forum.
Are you *that* desperate? I haven't worked with C++ in over three years... But I'll go take a look anyway...
-- LuisR
Luis Alonso Ramos
Intelectix - Chihuahua, Mexico
Not much here: My CP Blog!
The amount of sleep the average person needs is five more minutes. -- Vikram A Punathambekar, Aug. 11, 2005
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
