Re: Identifying the type of file - C# Discussion Boards

Michael Sync21-Aug-07 20:19

Michael Sync

21-Aug-07 20:19

Christian Graus wrote:
Use GDI+ to attempt to load a file and verify if it's an image.

Okay. Yeah. but what about other extension (eg: doc)?

Christian Graus wrote:
rite code that reads the file itself and attempts to identify the file format, which means you need to look for unique markers for each of these file types, and look for them.

I'm not clear about that. Could you please explain me again?

unique markers

like ??

Thanks and Regards,
Michael Sync ( Blog: http://michaelsync.net)

If you want to thank me for my help, please vote my message by clicking one of numbers beside "Rate this message". Why vote? Plz Read it here. Thank you.

aravinda77721-Aug-07 20:32

aravinda777

21-Aug-07 20:32

Something like how to identify those particular markers and stuff?

Christian Graus21-Aug-07 20:45

21-Aug-07 20:45

Michael Sync wrote:
but what about other extension (eg: doc)?

Exactly as I said

Michael Sync wrote:
I'm not clear about that. Could you please explain me again?

You'd have to know that the file format contains the word 'WORD' in the first four bytes, for example, and open the file and examine it for those known markers related to the known file format.

Michael Sync wrote:
like ??

I have no idea, I'm not the one with the issue.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Michael Sync21-Aug-07 21:59

Michael Sync

21-Aug-07 21:59

Thanks. Christian..

Christian Graus wrote:
Exactly as I said

Yeah.

Christian Graus wrote:
I have no idea, I'm not the one with the issue.

Okay.

Christian Graus wrote:
You'd have to know that the file format contains the word 'WORD' in the first four bytes, for example, and open the file and examine it for those known markers related to the known file format.

Oh.. I didn't know about that.. I will try to check this one.. thanks.

But i think that checking the extension might be more easier than checking the fist four bytes of each file, isn't it?

Christian Graus22-Aug-07 0:10

22-Aug-07 0:10

Michael Sync wrote:
ut i think that checking the extension might be more easier than checking the fist four bytes of each file, isn't it?

The first four bytes is an example off the top of my head. It's not real, Word doesn't do that. But, it may well do *something* to mark it's files.

And yes, checking the extension is going to work 99% of the time, and is a lot easier to do.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Michael Sync21-Aug-07 20:03

Michael Sync

21-Aug-07 20:03

aravinda777 wrote:
i handled identifying non-images

non-images files means "*.txt, *.dll, *.exe"?? How did you handle identifying those file type without checking the extension??

aravinda77721-Aug-07 20:13

aravinda777

21-Aug-07 20:13

In fact i am using the image to be displayed in a picturebox. When I try non-images, it gives an OutOfMemoryException.

This way I can identify non-images. Smile | :)

Luc Pattyn22-Aug-07 1:04

Luc Pattyn

22-Aug-07 1:04

There is no general solution to identifying a file's type; new file types are
created every day.
If you are only interested in whether it is a loadable image, then try to load
the image, and live with the possible exception.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

this weeks tips:
- make Visual display line numbers: Tools/Options/TextEditor/...
- show exceptions with ToString() to see all information
- before you ask a question here, search CodeProject, then Google

Thomas Krojer23-Aug-07 0:53

Thomas Krojer

23-Aug-07 0:53

Maybe you will find this site useful:

http://www.wotsit.org/

Greetings, Thomas

Help me in Invoking Dll's

Giorgi Dalakishvili21-Aug-07 22:07

Giorgi Dalakishvili

21-Aug-07 22:07

You can check only the extension but it might be incorrect. If you want tighter control then look for magic number[^] in that file Smile | :)

#region signature
my articles
#endregion

kandy_soliton21-Aug-07 19:38

kandy_soliton

21-Aug-07 19:38

Hi All,

I facing a problem which i have described briefly in the following paragraph.

Let me tell you a scenario where in the user has to choose any kind of dll he wants, rather be .Net Dll or Native Dll for a connection to his server.
In that he knows the function to Invoke.

I need to write a common user interface to invoke any kind of dll, based on the choice of the user. Is that possible ?. If so help me regarding the stratergy that i have to use or any examples of such accomplishment.

FYI
I know one software which is doing to most of the Dll's.

Thanks in Advance

Re: Help me in Invoking Dll's

Christian Graus21-Aug-07 20:00

Re: Help me in Invoking Dll's

21-Aug-07 20:00

You can late bind to .NET dlls, I'm not sure what you can do about native dlls, without having the pinvoke code already in your app.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Giorgi Dalakishvili21-Aug-07 22:09

Giorgi Dalakishvili

21-Aug-07 22:09

There are some articles here on cp which show you how to invoke function from a native dll without pinvoke code in the source.

#region signature
my articles
#endregion

QuickFix protocol

sujithkumarsl21-Aug-07 19:07

sujithkumarsl

21-Aug-07 19:07

hi, i am dealing with a stock market app, which is developing in c#.......... for trade purpose i want to use the QuickFix Protocol........ i was searching for sample codes for the same.... if any one have any idea pls contribute.............

My small attempt...

Re: QuickFix protocol

Ankit Aneja21-Aug-07 21:30

Ankit Aneja

21-Aug-07 21:30

http://www.codeproject.com/script/comments/forums.asp?forumid=1649&mode=all&userid=1392017&select=2073234&df=100&fr=12643.5#xx2073234xx[^]

this may help

Ankit Aneja
"Nothing is impossible. The word itself says - I M possible"

What is Reason? (plz reply) [modified]

Hum Dum21-Aug-07 19:00

Hum Dum

21-Aug-07 19:00

I had write code on text_change event of richText box in C#.net for wordwrap.

When i created the project and tested it its working fine, so i copy it make exe. Now problem is its showing some problem. so i check this code with oroginal code. In original code its working fine, but in copied code it showing problem.

The problem is like, after 3-4 line, at end of line its giving space in 2 letter like "Him" as "H i m", and adding "/n"at end of text.

Here maxLength is variable for no. of chracter like 65,66 etc per line, And if there is somthing wrong with code then plz help me.(not mismatch of { })

I want to know:

1. Code is for text_changed event & exact same in both, So why it like this?

2. Its only for text_change event and I dont think it has any relation with any other project part, i m using the text but after it has been put by the user.

The code for event is:

<br />
private void txtBody_TextChanged(object sender, eventArgs e)<br />
{<br />
    <pre>if(tbWordwrap.Pushed)
    {
       string[] tempArray = new string(txtBody.Lines.length);
       tempArray = txtBody.Lines;
 
       int Prevsel = txtBody.SelectionStart;
       string Op = "";
       int maxLength = cINI.dbUtils.Pref.DefaultEditorWidth;
       bool change= false;
 
      for(int cou = 0; cou < tempArray.Length ; cou++)
      {
        if (tempArray[cou].length > maxLength)
         {
           string words = tempArray[cou].split(' ');
           int currentLine Length = 0;
           string currentLine = ""; 
           foreach(string currentWords in words)
           {
            if(currentWord.Length > 0)
            { 
              if(currentword.Length >= maxLength)
               {
                Op += currentword.Insert(maxLength, "\r\n");
                break;
               }
             if(currentLineLength + currentword.Length + 1 < maxLength)
             {
                currentLine += currentword + " "; 
                currentLineLength += currentword.Length +1;
             }
             else
             {
               Op +=currentLine.Insert(currentLineLength, "\r\n");
               currentLine = currentWord; 
               currentLineLength = currentWord.Length;
             }
           }
         }
         if(currentLine !="")
          Op += currentLine;
          
          
          PrevSel++; 
          change = true;
      }
      else
      {
        Op += tempArray[cou] + "\r\n";
      }
   if(change)
   {
     txtBody.Text = Op;
     txtBody.SelectionStart = prevSel; 
   }
 }
}</pre><br />
<br />
<br />
 -- modified at 1:11 Wednesday 22nd August, 2007

Re: What is Reason? (plz reply)

Christian Graus21-Aug-07 19:59

How to print datagidview with form control

21-Aug-07 19:59

best guess, the control is different sizes on the two forms, and so one version is showing up bugs in your code that are not evident in the other version.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

tech-progg21-Aug-07 17:14

tech-progg

21-Aug-07 17:14

Hi techies,

m working on the student management project (School) on C# 2005 and sql 2005 (windows application), i completed 80% , it can

create class , add section , edit student seats in particular section, add subject, add subject to the

particular section, registration of the student acccording to the class and section also display vacant

seat while registration, create first term result , second term result and final term, it can give

grace if student flunking( max 20 marks) , all result are in datagridview , but now i stuk while

printing it , i want to print the datagridview with form control(text box and label) coz it contains the

student information. so any one gimmme favour. (it shud b include print preview , page setting, and

print dialog) .

<<tech-prog>>

Re: How to print datagidview with form control

Syed Mujtaba Hassan21-Aug-07 18:55

Syed Mujtaba Hassan

21-Aug-07 18:55

I think here[^] is the thing at CP that you want.

Mujtaba

"If both of us are having one one apple each and we exchange it, at the end we both will have one apple each. BUT if both of us are having one idea each and we exchange it, at the end both of us will be having two ideas each."

sQL with C# update question

falles0121-Aug-07 13:39

falles01

21-Aug-07 13:39

HI,

I am trying to write an SQL update query with c# code.
This is my situation.

I have a number of winforms and a sql server database. On one form I have drop down lists which are populated with the database rows by table adaptors.

This is what I need to do.
User selects a name from the drop down and clicks update which opens up a new form (class). In this new class I need to write an update statement to say update employees where '" + empNamecomboBox.Text.ToString() + "'. Basically to make sure we only update the selected employee, I want to say where the previously selection has been made. The only thing is I can't reference empNamecomboBox.Text because it belongs to another class.

Can you please helpe me? I've only got a few days to complete this.

Siann Confused | :confused:

Christian Graus21-Aug-07 13:41

21-Aug-07 13:41

So, basically you want to pass the string in question into the constructor of the new form, so that it knows where to look.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

falles0121-Aug-07 13:47

falles01

21-Aug-07 13:47

Well I was told to use empID which is the primary key to pass to the constructor like this. But then I tried the same update statement to no evail. I have only been programming for 2 months. Do I use empID somewhere in the update query?

public UpdateEmployee(int employeeID)
{
this.employeeID = employeeID;

InitializeComponent();
}

public int employeeID;

Christian Graus21-Aug-07 17:00

21-Aug-07 17:00

falles01 wrote:
public int employeeID;

Why on earth is this public ? If you've been given this code to work on, the people you work with are no better skilled than you, which does not bode well for your future.

Yes, you should be using this variable, instead of blindly copying code that relies on a control that's in another form. And, if you can't work that out, then you have some learning to do which excludes you from being able to write code that anyone should be expected to pay for.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Christian Graus21-Aug-07 17:19

21-Aug-07 17:19

string sql = "UPDATE employees SET Firstname = '" + employeeTextBox.Text + "' Where EmployeeID = '" + employeeID + "'";

I am assuming the textbox is on the second form, therefore that control is correct ? Also, employeeId is an int, why is it stored as a string in the database ? If it's not, then change to this:

string sql = "UPDATE employees SET Firstname = '" + employeeTextBox.Text + "' Where EmployeeID = " + employeeID;

Note, I made a typing error, and so I lost the name of the textbox, and just made something up, you may need to fix that, to make it all work. The brackets are superfluous in either case.

And again, this is open to injection attacks. That means, someone can enter an employee name which erases your entire database.

Is this an assignment, or is it paid work ? If it's an assignment, I apologise for being a bit harsh previously, but if you've been given this code and told to work on it, that sounds like a job task. And, if that's true, you need to make the code more secure ( an assignment obviously is not as important, at this stage of your learning curve )

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )