在C＃中使用streamReader类

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 eg 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

You can use string.Split( ) on your string and later use the array index rather than string positions to convert the numbers. Splitting the string on white space will remove the white space from the string. Something like:

public myRows(string str)
       {
          string[] splitArray = str.Split(); //split on white space
          if(splitArray.Length > 7)
              {
               Number1 = Convert.ToDecimal(splitArray[0]);
               //,....... So on
              }
       }

Answer 2

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 )

Answer 3

using Split method split your line into 8 parts. Last one will be your date.

var parts = line.Split(new char[]{' '}, 8, StringSplitOptions.RemoveEmptyEntries);

Number1 = Decimal.Parse(parts[0]);
Number2 = Decimal.Parse(parts[1]);
......
......
DateTime Date1 = DateTime.ParseExact(parts[7],"ddd MMM dd HH:mm:ss yyyy",CultureInfo.InvariantCulture);