Question

  public class myRows
   {
       public decimal Number1 { get; set; }
       public decimal Number2 { get; set; }
       public decimal Number3 { get; set; }
       public decimal Number4 { get; set; }
       public decimal Number5 { get; set; }
       public decimal Number6 { get; set; }
       public string Date1 { get; set; }

       public myRows(string str)
       {
               Number1 = Convert.ToDecimal(str.Substring(3, 7));
               Number2 = Convert.ToDecimal(str.Substring(15, 8));
               Number3 = Convert.ToDecimal(str.Substring(24, 8));
               Number4 = Convert.ToDecimal(str.Substring(36, 8));
               Number5 = Convert.ToDecimal(str.Substring(47, 8));
               Number6 = Convert.ToDecimal(str.Substring(58, 8));
               Date1 = str.Substring(65, 25);
       }
   }

i then read the text file data like

var myRows = new List<myRows>();
var myR = new StreamReader(txtFileToImport.Text);
while (!myR.EndOfStream)
      {
          string s = myR.ReadLine();
          if (!String.IsNullOrEmpty(s.Trim()))
          {
             myRows.Add(new myRows(s));
          }
          }
  myR.Close();
  dataGridView1.DataSource = myRows;

The problem am having is pre-determining the startIndex and length of the white space between the column values in the text file e.g here Convert.ToDecimal(str.Substring(3, 7));

White space between column values isn’t uniform, it can be 5 between column 1 and 2 and then be 8 between column 7 and 8.

Currently, i have to know in advance the index at which the white space starts and ends. Is there away i can dynamically get the start Index of the white space and its length with out getting to look at the text file to be processed?

What i really need is the parameters passed to str.Substring(,) not to be hard corded.

@Habib: sample text file is here

Answer 1

Use String.Split on the space character with the StringSplitOptions.RemoveEmptyEntries option. This will remove the empty fields effectively leaving only fields with your data.

Given a line of your text file in line, your code would look something like this:

var fields = line.Split(" ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
var Number1 = Convert.ToDecimal(fields[0]);
var Number2 = Convert.ToDecimal(fields[1]);
// etc.

Since your date data is broken up into several descrete fields (day of week, month, day, etc) you’ll ‘reassemble’ them through the fields they’ll occupy and assign to your Date1:

var Date1 = string.Format("{0} {1} {2} {3} {4}", fields[7], fields[8], fields[9], fields[10], fields[11]);

Of course in production code you’ll want to validate a couple things:

• You’ve read the expected number of fields
• That you can safely convert your string field values to Doubles (for this
  use Double.TryParse)