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Hi,
I want to write a self updating application. What can be the best approach? Whether i should go for Click once application deployment, or write my own code ( using BITS etc) or any other method. Please guide me in this regard.
Regards,
Wasif Ehsan.
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I have a public field in my class
[XmlIgnore]
public string MyVar;
But at runtime I need to remove this decoration. Is there a way to remove it at runtime? I tried the attributes collection in the PropertyInfo. That doesn't work
Or if I could add the XmlIgnore at runtime. That would work also. But, the attributes collection doesn't allow me to do such a thing
--------------------------------------------------------
1 line of code equals many bugs. So don't write any!!
My mad coder blog
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Hi,
Could you spare some time to help me with a small problem?
I need to perform encryption and decryption using the DES algorithm.
This is the way I want the program to work :
My form has 4 textboxes -
1) tbPlaintext --- For the user to enter the plaintext
2) tbCiphertext --- For displaying he ciphertext
3) tbKey --- For displaying the key
4) tbIV --- For displaying the Initialization Vector
and 2 buttons -
1) Button1 --- When clicked performs encryption using key form tbKey and the IV from the string - "init vec"
2) Button2 --- When clicked performs decryption using the key in tbKey and the IV "init vec"
The user enters the plaintext -"Hello world" and the key - "qwertyui" and clicks the Button1. The ciphertext appears in the textbox tbCiphertext ("SGVsbG8gd29ybGQ=").
This part works fine.
Now when the user clicks the Button2 , after clearing the text in tbPlaintext, the plaintext "Hello world" should appear in tbPlaintext. But what I get is "U0dWc2JHOGdkMjl5YkdRPQ==". How do you explain that?
What should I do to get my original plaintext?
The MSDN article "How To: Create an Encryption Library in .NET 1.1" at the following URL helped me with the code-
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnnetsec/html/SecNetHT10.asp
Is there something I'm missing?
Please help me as soon as possible so I can proceed with my project.
- Sreerag Gopinath P C
EMAIL : sreerag.gopinath@gmail.com
PHONE : +919447489699
*********************************************************
The relevant source code is as follows -
-----------------------------------------------
/* ENCRYPT USING DES ALGORITHM */
private void button1_Click(object sender, System.EventArgs e)
{
if (tbKey.Text == "")
MessageBox.Show("Enter some key");
else
{
if (tbKey.Text.Length == 8)
{
DES des = new DESCryptoServiceProvider();
des.Mode = CipherMode.CBC;
byte[] plaintext = Encoding.ASCII.GetBytes(tbplaintext.Text.ToString());
byte[] key = Encoding.ASCII.GetBytes(tbKey.Text.Trim());
byte[] IV = Encoding.ASCII.GetBytes("init vec");
des.Key = key;
des.IV = IV;
ICryptoTransform transform = des.CreateEncryptor(des.Key,des.IV);
MemoryStream memStreamEncryptedData = new MemoryStream();
memStreamEncryptedData.Write(plaintext,0,plaintext.Length);
CryptoStream encStream = new CryptoStream(memStreamEncryptedData,transform,CryptoStreamMode.Write);
byte[] ciphertext = memStreamEncryptedData.ToArray();
tbCiphertext.Text = Convert.ToBase64String(ciphertext);
string msg = String.Format("KEY : {0}\r\nIV : {1}",Convert.ToBase64String(key),Convert.ToBase64String(IV));
MessageBox.Show(msg);
// tbKey.Text = Convert.ToBase64String(des.Key); // The key seems to have changed
// tbIv.Text = Convert.ToBase64String(des.IV); // So does the Initialization Vector
// stored_key = des.Key; // Storing these for later retrieval
// stored_IV = des.IV; // does not produce the expected results either.
encStream.Close();
}
else
{
MessageBox.Show("Key length should have 8 characters");
}
}
}
/* Decrypt DES encrypted text */
private void button2_Click(object sender, System.EventArgs e)
{
try
{
DES des = new DESCryptoServiceProvider();
des.Mode = CipherMode.CBC;
byte[] ciphertext = Encoding.ASCII.GetBytes(tbCiphertext.Text);
byte[] key = Encoding.ASCII.GetBytes(tbKey.Text); // Prompts user to enter the key
// byte[] key = Encoding.ASCII.GetBytes("qwertyui"); // Even this does not seem to work--Why?
byte[] IV = Encoding.ASCII.GetBytes("init vec");
// byte[] IV = Encoding.ASCII.GetBytes(tbIv.Text); // Does not appear to work either
des.Key = key;
des.IV = IV;
// des.Key = stored_key; // Retrieving the Key and IV form already stored
// des.IV = stored_IV; // variables does not work either
ICryptoTransform transform = des.CreateDecryptor(des.Key,des.IV);
MemoryStream memDecryptStream = new MemoryStream();
memDecryptStream.Write(ciphertext,0,ciphertext.Length);
CryptoStream cs_decrypt = new CryptoStream(memDecryptStream,transform,CryptoStreamMode.Write);
byte[] plaintext = memDecryptStream.ToArray();
tbplaintext.Text = Convert.ToBase64String(plaintext);
cs_decrypt.Close();
}
catch(Exception x)
{
MessageBox.Show(x.Message);
}
}
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you're mixing with the base64 encoding. Your sequence is:
Encryption:
get bytes of plaintext
encrypt
display base64 encoded ciphertext
Decryption:
get bytes of ciphertext
decrypt
display base64 encoded result
but better and working solution ought to be
Decryption:
decode the ciphertext bytes from the base64 (FromBase64String)
decrypt
get string from bytes
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Hi everybody
I'm trying to send a large file accross a network.
the problem is that I'm losing many chunks.
At the beginning I tried to split the file myself and send it, but I had a lot of lost data, so I read about BufferedStream class that can take care of the chuncks by itself.
so, for sending the file I wrote:
stream = client.GetStream();
<br />
BufferedStream buff = new BufferedStream(stream);<br />
buff.Write(fileBytes, 0, fileBytes.Length);
<br />
buff.Flush();<br />
stream.Close();
for getting the file I wrote:
socket = listener.AcceptSocket();<br />
NetworkStream stream = new NetworkStream(socket);<br />
<br />
byte[] filebyte = new byte[filesize];
<br />
BufferedStream buff = new BufferedStream(stream);<br />
int readByte = 1;<br />
<br />
while(readByte > 0)
readByte = buff.Read(filebyte, 0, filebyte.Length);<br />
<br />
File.WriteAllBytes(filename, filebyte);<br />
<br />
buff.Flush();<br />
stream.Close();
The problem is that I still lose data, I really don't know what else to do.
ANY HELP will be highly appriciated!!! 
Thanks!
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IS this at all possible? thanks
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im working on an application p2p filesharing and messaging.
im trying to do it over HTTP:80. packets can be dropped routers and firewalls, so i want to use port 80.
is it possible to communicate between clients 2 clients and clients to server over HTTP without installing IIS (except servers)? 
thanks!!
asamay
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Hi ,
I have a running
instance of word got from Marshal.GetActiveObject("Word.Application");
in my c# application. So how do i get the absolute path of the word document that is open?
Luck is Opportunity with hardwork
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...
Word.Application w= new Word.Application();
w = (Word.Application) System.Runtime.InteropServices.Marshal.GetActiveObject("Word.Application");
MessageBox.Show(w.ActiveDocument.Path);
...
UMS
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Thanks umseker..
It works..
Luck is Opportunity with hardwork
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Hello Everyone:
I am working on an app (windows) in which I need to provide a functionality to create object connectors (using mouse events). Kinda like when you try to make a DTS package in SQL Server you connect two ojbect and it draws a nice graphics to represent the connected objects. Or Table Designer when you try to relate two fields in seperate tables.
Any help will be appreciated. Thanks.
Best Regards,
Robert
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Also can you decrypt the content from the database and recreate the file?
thanks in advance.
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Hi,
Can you recommend a book on C# 2005 (windows or web) with excel/word please?
I would like to learn programming office applications (excel or word) with c# 2005 (asp.net 2.0 or windows).
Thanks
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Does anyone know if there is a way to access command line arguments from one running application in another application. I want to have a windows service that looks for other running apps and runs them when necessary. Sometimes there may be more than one instance running with different arguments, so I need a way to see what arguments the running instance is using. I tried looking at processes that I get when calling GetProcessesByName and then looking at StartInfo Arguements, but it appears to be empty even when I have passed in parameters. I know my parameters have been accepted because I an display them in a message box. Any help on this would be greatly appreciated.
Sean
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Hi guys,
Please I need some help. I am totally lost on this and have used all my thinking power to deal with this issue and no luck. I have an application that uses System.Web.Mail to transmit emails, in every 5-6 emails that go out one stalls giving the above error with inner exception as follows:
The transport failed to connect to the server and sometimes it says The transport lost it's connection to the server.
We have a mail marshal server that also acts as a dummy smtp server to filter the emails and that is where I am directing these emails to. This dummy server acts as a filter to the emails and diverts them to the main email server with a port not 25 hence I can't divert them through that main server. Do you think this could be a problem?
Dummy server is the SMTP server I am using and has a port 25. Our SMTP server configurations are through Exchange.
Please any suggestions will be very helpful.
sasa
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Hi guys, i need to execute such a file and supply it arguments, i've looked around and found the "System.Diagnostics.Process.Start()" method, it works great, but i want controll over the executed application... or at least run it in a minimized window state...
any suggestions?
(The executable is a program written in c)
Thanks in advance,
Erik.
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Process proc = new Process();
proc.StartInfo.WindowStyle = ProcessWindowStyle.Minimized;
proc.StartInfo.FileName = "thefile.exe";
proc.Start();
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Thanks guys!
Ok next question... the executable exe file gets input from the user (using scanf)
is there a way to supply it arguments without changing the source code of the executable?
(by changing the main to receive parameters and modifing the source code accordingly)
I guess it has something to to with adding values to the input buffer of that application...?
Thanks in advance,
Erik.
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You can supply arguments to the executable by changing the ProcessStartInfo.Arguments property. Is that what you mean?
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How about:
myProcess.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
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Hi all dear friends,
I have a win. service, and I try to read the current user name,
the following methods DONT work, please help.
1. Way : --> System.Security.Principal.WindowsIdentity.GetCurrent().Name;
2. Way : --> Environment.UserName;
these are dont work, becuase, win service run as a account "system" default.
any other ideas ?
Cheers...
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