I have the following situation:
- I need to iterate through many streamed, comma-delimited, input files
(with different numbers of comma de-limited fields and internal
structures); re-format them (selecting common fields from the different
files); and output them into a common file.
- The input files all have similar characteristics - I need to open them,
iterate through each line, determine how many commas there are per line,
and close them. It is the detailed formatting for each file that is
different.
- To achieve this I can define a parent class (FileMgr), and inherit the
majority of the functionality in file-specific sub-classes (FileMgrType1,
FileMgrType2,...). I then implement a file-type specific Format method in
the child classes.
So far, so good.
>From the client side, I would like to iterate in a loop, processing a new
file on each re-pass. At the start of iteration I would like to open the
new input file, and create a file-specific object that can format and hold
the variables for that type of file - using as few fileType specific lines
of code as possible. I include a (contrived) sample of the sort of thing
that I would like to do.
I (unsuprisingly) get compilation errors - error CS0128, local variable
already defined in this scope - because I am trying to 're-use' the same
variable name for different objects in my Main.
I could cut and paste the same code (with slightly different variable
names) - but if I need to open 50 different files, then this becomes
cumbersome.
Is there anyway of achieving what I want to do?
Regards
-Steve Simpson
using System;
using System.IO;
using System.Text;
namespace PolyClient
{
/// <summary>
/// Summary description for Class1.
/// </summary>
///
// A class to format & hold an input record as an intermediate,
formatted object
class FileMgr
{
public int numberFieldsInInput;
public string [] fields;
// a whole load of common attributes, and associated public
accessors to hold the data elements
// public string TodaysDate;
// public int RecordId;
// etc. etc.
virtual public void Format ( string foo)
{
// extract the field values from the string, and
put into the class members.
}
}
// A class to do formatting for Type1s
class FileMgrType1 : FileMgr
{
public void setnumberFieldsInInput()
{
numberFieldsInInput = 10 ;
}
override public void Format (string foo)
{
fields = foo.Split(new Char[] {','});
// do a load of formatting here
}
// A class to do formatting for Type2s
class FileMgrType2 : FileMgr
{
public void setnumberFieldsInInput()
{
numberFieldsInInput = 15 ;
}
override public void Format (string foo)
{
fields = foo.Split(new Char[] {','});
// do a load of formatting here
}
}
class Class1
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main(string[] args)
{
int i;
const int noFiles = 2;
string currentRecord;
// Create an output file here...
for (i=0; i < noFiles; i++)
{
switch (i)
{
case 1:
StreamReader inFile
=new StreamReader("type1.txt", Encoding.ASCII);
FileMgrType1
fileMgr = new FileMgrType1();
break;
case 2:
StreamReader inFile
=new StreamReader("type2.txt", Encoding.ASCII);
FileMgrType2
fileMgr = new FileMgrType2();
break;
}
while ((currentRecord =
inFile.ReadLine()) != null)
{
fileMgr.Next
(currentRecord);
// Lots of other stuff to
do here
// Output contents of
fileMgr public members into output file here...
}
inFile.Close();
i++;
}
}
}
}
}
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