Re: Parse a text file into an object - C# Discussion Boards

Re: How to extract Image metadata

28-Aug-06 8:49

Hi guys,

I want to extract some specific image metada from an .jpg file. I explored through the codeproject and msdn as well as google but found nothing (I mean not exactly nothing but only codeparts and info which are not I want).

Lets me explain in more detailed : I edit some image information from Photoshop (right-click on the image window header > file info > description tab).. After editing whenever I load an the image I want to see the description, title, author, keywords etc..
With the PropertyItem I can only view the description, author and creation time (other info doesn't worth for me).

So my question is how can I read AND write specific metada pieces ?

.:: Something is Wrong ::.

Eric Dahlvang28-Aug-06 11:33

Eric Dahlvang

28-Aug-06 11:33

This might help: Retrieve detailed information of a File[^]

--EricDV Sig---------
Some problems are so complex that you have to be highly intelligent and well informed just to be undecided about them.
- Laurence J. Peters

Parse a text file into an object

AndyHug28-Aug-06 8:41

AndyHug

28-Aug-06 8:41

hi,

I have an text file grouped into records that I need to be parsed into a object. The record is like :

H10000<cr> ( H from header of the record )
I1,name,age,sex (Information1)
C1,text... (Comment 1 for Information1)
....
Cn,text... (Comment n for Information1)
I2,name,age,sex (Information2)
C1,text... (Comment1 for Information2)
....
Cn,text... (Commentn for Information2)
...
In,name,age,sex (Information n)
C1,text... (Comment1 for Information n)
....
Cn,text... (Commentn for Information n)

E1 (End message)

There is a class for each Tag (H,I,C,E) and a Record class that is the superclass for the classes(H,I,C,E) . I need to parse this file and store the informations from the records into a object using generics. For the informations I must use a list. I also need the reverse operation : from object to write to file.

I realize that the code must be written by myself but I would appreciate some general help about how to create the object from file

thanks

Ed.Poore28-Aug-06 9:14

Ed.Poore

28-Aug-06 9:14

Well seeing as it appears to be a CSV file you can read in the whole file line by line and split it to get various parameters.

while (stream.Peek() != -1)
{
	string[] cells = stream.ReadLine().Split(',');
	// Create object through constructor or some other method.
}

Hope that gets you started.

As of how to accomplish this, have you ever tried Google?

Not Active28-Aug-06 9:15

Not Active

28-Aug-06 9:15

Serialization

only two letters away from being an asset

SomeGuyThatIsMe28-Aug-06 9:16

28-Aug-06 9:16

If you could rewrite the file using xml tags .NET has some nice built in support for reading and writing that would do exactly what you want, shoot me an email and i'll send you some examples(mine are too long to post here, but only because i load a lot of data from the files, and do the same for writing them). Another, probably not very good way is to open the file into a stream reader and use the ReadLine() method to grab each line and put it into a string, then fall through a switch on the first character so you know what kind of object to use, and writing may be a bit more difficult it'd depend on how you deal with the data in your program...personally i'd prefer a foreach and then use a switch on the object type, as its simple, and easy to fix, but it doesnt work everywhere...if you'd like examples shoot me an email.

Guffa28-Aug-06 9:35

Guffa

28-Aug-06 9:35

SomeGuyThatIsMe wrote:
If you could rewrite the file using xml tags

Of course he can't change the school assignment. Wink | ;)

---
b { font-weight: normal; }

SomeGuyThatIsMe28-Aug-06 9:42

28-Aug-06 9:42

why not? i always did. I didnt see anything about a school assignment, but i'm mostly blind, so i prolly missed it, and just assumed that it was for work of some kind...but the stream reader method should work, fairly easily, even if it is a bit slow.

AndyHug28-Aug-06 9:41

AndyHug

28-Aug-06 9:41

I must select the "not very good way" and to open the file into a stream and use ReadLine() to grab each line and put it into a string, then fall through a switch on the first character so I know what kind of object to use
This part I know how to do it ... The don't know part is how to use the fields and C# classes to create this single object I need. Some one sent me some code in VB.NET that I think it seems like i need, only that I need it in C#. If you have something similar please send at least some explanations.

The VB code :

Private Sub ParseFile(ByVal filename As String)
Dim headers As New HeaderCollection
Dim reader As IO.StreamReader
While reader.Peek <> -1
Dim line As String = reader.ReadLine
Select Case line.Substring(0, 1)
Case "H"
headers.Add(line)
Case "I"
headers.LastItem.InformationList.Add(line)
Case "C"
headers.LastItem.InformationList.LastItem.Comments.Add(line)
Case "E"
headers.LastItem.Footer = line
End Select
End While
End Sub
Private Sub WriteFile(ByVal filename As String, ByVal headers As HeaderCollection)
Dim writer As IO.StreamWriter = New IO.StreamWriter(filename, True)

For Each h As Header In headers
writer.WriteLine(h.Text)
For Each i As Information In h.InformationList
writer.WriteLine(i.Text)
For Each c As Comment In i.Comments
writer.WriteLine(c.Text)
Next
Next
writer.WriteLine(h.Footer)
Next

writer.Flush()
writer.Close()
End Sub

Public Class Header
Private _informtions As New InformationCollection
Public Text As String
Public Footer As String
Public Property InformationList() As InformationCollection
Get
Return _informtions
End Get
Set(ByVal Value As InformationCollection)
_informtions = Value
End Set
End Property
End Class
Public Class Information
Private _comments As New CommentCollection
Public Text As String
Public Property Comments() As CommentCollection
Get
Return _comments
End Get
Set(ByVal Value As CommentCollection)
_comments = Value
End Set
End Property
End Class
Public Class Comment
Public Text As String
End Class
Public Class HeaderCollection
Inherits CollectionBase
Public Overloads Sub Add(ByVal Text As String)
Dim h As New Header
h.Text = Text
List.Add(h)
End Sub
Default Public Property Item(ByVal index As Integer) As Header
Set(ByVal Value As Header)
Me.List(index) = Value
End Set
Get
Return DirectCast(Me.List(index), Header)
End Get
End Property
Public ReadOnly Property LastItem() As Header
Get
Return DirectCast(Me.List(Me.List.Count - 1), Header)
End Get
End Property
End Class
Public Class InformationCollection
Inherits CollectionBase
Public Sub Add(ByVal Text As String)
Dim i As New Information
i.Text = Text
List.Add(i)
End Sub
Default Public Property Item(ByVal index As Integer) As Information
Set(ByVal Value As Information)
Me.List(index) = Value
End Set
Get
Return DirectCast(Me.List(index), Information)
End Get
End Property
Public ReadOnly Property LastItem() As Information
Get
Return DirectCast(Me.List(Me.List.Count - 1), Information)
End Get
End Property
End Class
Public Class CommentCollection
Inherits CollectionBase
Public Overloads Sub Add(ByVal Text As String)
Dim c As New Comment
c.Text = Text
List.Add(c)
End Sub
Default Public Property Item(ByVal index As Integer) As Comment
Set(ByVal Value As Comment)
Me.List(index) = Value
End Set
Get
Return DirectCast(Me.List(index), Comment)
End Get
End Property
End Class

Thanks

SomeGuyThatIsMe28-Aug-06 10:09

28-Aug-06 10:09

ick, i hate VB, mostly because the vast majority of examples you find for it never bother with strict typing, which if you're going to translate to c# is very necessary.

ok i'm going to assume that all this needs to do is read the file, then write that same data to a different file, i havnt messed with generics, but i would either make the "superclass" have properties of the other types, or make the other types like header or comment inherit the superclass, but i havnt messed w/ generics so there's prolly some slick, cool way to do this that i'm not aware of.

but to read the file in c# (you get to declare the varibles cuz i'm too lazy to type that), i'm also going to assume that the super class has properties of the type of the other classes so i can get to them like record.header.*something a header has or does*

while(!endOfFile){//endOfFile is a bool initialized to false
line = reader.ReadLine();//line is a string, guess what reader is
firstChar = line.SubString(0,1);//pretty easy so far right?
switch(firstChar){
Case 'H':
record.Header.value = line;/*record is an instance of the superclass, value is the property you want the header stored in, if you want the first letter gone you'll have to remove it with a line = line.Remove statement*/
break;
Case 'I':
//do whatever you need to do to save the information in the record object
break;
/*keep going until you've added everything for a certian record..if you can have mulitple comments the comments property of the record class may need to be an array or you'll have to figure out some other way to handle it*/
}//end switch
recordList.Add(record);/*adds the record object to an ArrayList of record objects..or you could use a normal array if you know how many records you'll have*/

}//end while dotn forget on case 'E' you have to set end of file to true so the loop ends

to write the file you'll just need a StreamWriter then just use a foreach loop to get your stuff back

foreach(Record r in RecordList){

writer.write(r.header.value.ToString());//so on and so forth, you'll have to so something speical for the comment part if you can have more than one...if you used an array or array list you can just loop through the comments like you are the records in record list

}//end foreach

and tada you're done...i think, i'm not gaurenting that this code will work( i wrote it on this site not in visual stuio and i havnt tried it, but the methodology does work i've used that several times before. if you need anymore help or have any questions shoot me an email to dalaji@excite.com(its my spam account so put CodeProject help or something like that in the subject so i dont delete you)

AndyHug30-Aug-06 4:31

AndyHug

30-Aug-06 4:31

My biggest problems aren't the parser but the classes , the fields and propreties of those classes. At the moment I have the following classes :

Record ( which is the superclass )
- MessageHeaderRecord ( the superclass for the next classes ) :
- InfosRecord ( the class for the I tag
representing the informations from text )
- CommentRecord
- OrderRecord
- ResultsRecord
- TerminatorRecord

For each of this classes I have a corresponding class (MessageHeaderRecordFields ,...) in which I created the fields to put the infos from the file.

So far so good ...

MessageHeaderRecord beeing the superclass for the rest of classes I put inside of it a generic List :

private List<informationrecord> m_Infos = new List<informationrecord>()

internal List<informationrecord> Infos
{
get
{
return m_Infos;
}
}

and the constructor is

internal MessageHeaderRecord()
{

RecordType = RecordType.MessageHeaderRecord;
m_Fields = new MessageHeaderRecordFields(); //

}

I did this because I want to access the objects as follows :

Message MyMessage = new Message();

MyMessage.Infos[3].Fields.SequenceNumber = "1";
MyMessage.Infos[3].Fields.InfoName.LastName = "John";

// Create a new info
int nInfoIndex = MyMessage.AddNewInformation(); (*1)
// Set the info specific data such as name, age, etc. for the info we just addded
MyMessage.Infos[nInfoIndex].Fields.InfoName.LastName = "John";

// Add an order record for this patient
int nOrderIndex = MyMessage.Infos[nInfoIndex].AddNewOrder(); (*2)

// Set the order specific information for the new order
MyMessage.Infos[nInfoIndex].Orders[nOrderIndex].Fields.OrderID = "11";

// Add a comment to this order
MyMessage.Infos[nInfoIndex].Orders[nOrderIndex].AddNewComment(); (*3)

// Set the text for the new comment
MyMessage.Infos[nInfoIndex].Orders [nOrderIndex].Commment.Fields.CommentText = "I am a comment.";

// Add a Result to this order
nResultIndex = MyMessage.Infos[nInfoIndex].Orders[nOrderIndex].AddNewResult();

// Set the new result's data
MyMessage.Infos[nPatientIndex].Orders[nOrderIndex].Results[nResultIndex].Fields.SequenceNumber = "333"; (*4)

So my problems redefined would be

(*1) - In which class to put the AddNewInformation() method

(*2) - In which class to put the Orders List and where to put the AddNewOrder() method

(*3) - In which class to put the Comment List and where to put the AddNewComment() method

(*4) - Same with Results List and AddNewResults() method

Please help me again with this issues because I really cant figure them out.

Thank you in advance

SomeGuyThatIsMe30-Aug-06 5:02

30-Aug-06 5:02

*1 you'd have to put the AddNewInformation method into the class that MyMessage instantiates(sp?) so since MyMessage is of type Message AddNewInformation would have to be in the Message class, or in the class that Message inherites. the same with the others...if you want to add a record to orders, then orders must implement that function, if you're sure you want to access the objects like this.

it looks like you want to access the rest of the properties like they're in a predefined array...if you want your Add** methods to work like the ArrayList.Add() method you dont need the [], just call the add function, using a predefined array isnt a very good idea unless you always know the number of the elements you'll need..and setting the array to be overly large is just a bad habit to get in. you could just have the comment, info, orders, etc.. classes store info about themselves and then have Record contain arrayList properties for each that way you can still use [] to specify records, and they'll be dynamically sized...and you could either put the Add*** methods in Record and just have them add new instances of the respective class to the list. also if you have the Add*** methods take a parameter or two you could save yourself soem typing at least w/ the coments, and set the text for the comment when you add it. this may be possible with the other add methods but i'd have to see your code. if this didnt help you could send me an email w/ some of your class definitions, thats about the only way.

Oh, if i'm wrong about something feel free to correct me, i'm mostly self taught and generally have a different way of looking at and explaining things, than most other programmers i've talked to, sometimes my way works better sometimes its way worse.

HTH
John

Progress Bar: File Copy

numbers1thru928-Aug-06 8:13

numbers1thru9

28-Aug-06 8:13

Ive been trying to figure this problem out. I have a status strip with a progress bar in it. I want to use that pb to increase as the file is copying. Someone suggested I have an event that occurs every few bytes or so to increase the pb. I have looked and looked for a way to do this only to return to not have anything. Any help or a link that can do this would be greatly appreciated. Thanks.

pasha2k28-Aug-06 8:31

28-Aug-06 8:31

try to use the Refresh() method for your progress bar after each PerformStep()

regards..

.:: Something is Wrong ::.

mav.northwind28-Aug-06 8:32

mav.northwind

28-Aug-06 8:32

With BCL classes you're out of luck here.
The built-in classes don't give you any progress update while copying.
You can either write your own file copy routine that's firing an event from time to time or p/invoke CopyFileEx.

Regards,
mav

--
Black holes are the places where god divided by 0...

pasha2k28-Aug-06 8:57

28-Aug-06 8:57

In my app, Refresh() does the job..
But you can also try

..
..
//after a specific amount of bytes are copied
UpdateProgressBar();
..
..
public delegate void UpdateDelegate();
private void UpdateProgressBar()
{
if (statusToolStrip.invokeRequired)
{
UpdateDelegate delegate = new UpdateDelegate();
delegate.Invoke(UpdateProgressBar);
}
else
{
progressBar.PerformStep();
statusToolStrip.Refresh();
}
}
..
..

.:: Something is Wrong ::.

mav.northwind28-Aug-06 9:30

mav.northwind

28-Aug-06 9:30

That's not the question.
How can you update the progress bar when you don't get any progress notification from File.Copy() ?

Regards,
mav

--
Black holes are the places where god divided by 0...

Nader Elshehabi28-Aug-06 8:35

Nader Elshehabi

28-Aug-06 8:35

Hello

Pardon me for asking this intuitive question, but...

How do you copy your file exactly?? Big Grin | :-D

Regards

pasha2k28-Aug-06 8:51

28-Aug-06 8:51

.. using System.IO;
..
..

File.Copy(source,destination);
..
..

.:: Something is Wrong ::.

Nader Elshehabi28-Aug-06 9:54

Nader Elshehabi

28-Aug-06 9:54

Hello

Mav is right. Yet!! As my habit of making crazy suggestion;P, you can make a timer that checks the destination file's size each -let's say- 50 milliseconds, and updates the ProgressBar according to the percent of the current size/Total size.

Regards