How to work with ArrayList in C#?


Hello group,

I'm reading a log file where I need 4 parameters from each line of it so I'm using ArrayList but the problem is that due to being new to C# I'm not sure if this works I just know how to create and add to an ArrayList so basically what I need is to know how to create a dynamic array, since the lines of log file are not defined and could change.
Any help is appreciated.

Regards,
ak
akohanAsked:
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itsmeandnobodyelseCommented:
An ArrayList is a dynamic array.

You would create a new one by

  ArrayList list = new ArrayList();

You can add entries by using the Add member function:

   if (Directory.Exists(directory))
  {
      String[] e = Directory.GetFiles(directory, "*.dll");
      for (int i = 0; i < e.Length; i++)
     {
          list.Add(e[i]);
     }
  }

If you search for C# ArrayList sample in MSDN or Google you'll get cillions of working samples.

e. g. at  http://msdn.microsoft.com/en-us/library/z9hsy596(VS.80).aspx?ppud=4
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akohanAuthor Commented:


Thanks indeed.

regards,
ak
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Göran AnderssonCommented:
Unless you are stuck with framework 1.1, you should not use ArrayList at all. You should use a strongly types List<T> instead.

As you have several values from each line, you can for example use a list of string arrays:

List<string[]> log = new List<string[]>();
foreach (string line in File.ReadAllLines("log.txt")) {
   log.Add(line.Split(' '));
}

Or you can create a class to represent a log line:

public class LogLine {
   public string Param1 { get; private set; }
   public string Param2 { get; private set; }
   public string Param3 { get; private set; }
   public string Param4 { get; private set; }
   public LogLine(string line) {
      string[] params = line.Split(' ');
      Param1 = params[0];
      Param2 = params[1];
      Param3 = params[2];
      Param4 = params[3];
   }
}

The you use a list of LogLine objects:

List<LogLine> log = new List<LogLine>();
foreach (string line in File.ReadAllLines("log.txt")) {
   log.Add(new LogLine(line));
}
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