Trouble with lilstbox and arrays

Vulpes is correct, I used an array of strings for my example code, I did not test using a listBox1 so as Vulpes says, ToString() is needed.

The problem is that listBox1.Items[i] returns an object, not a string.

You therefore need to replace this expression, wherever it occurs, with listBox1.Items[i].ToString() to avoid the errors.

Hi I keep getting 7 errors saying : 'object' does not contain a definition for 'Substring' and no extension method 'Substring' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?)

I've got these for the referance :

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Text.RegularExpressions;

Am I missing something out because both your code looks like it would work!!!Ahhhh
Thanks Mike

If the items in list box 1 are consistent (as you have shown) then the following will give you what you want, you don't need to use replace or insert, just do it.


  listBox1.Items.Add("05/7/11John");
  listBox1.Items.Add("05/11/11Sara");

  private void button1_Click(object sender, EventArgs e)
  {

  //assuming that each item in the list box begins with the date you are wanting to move to listbox2
  //and the format is as per your example, then the following code will do what you are after.
  //notice that I am not inserting or replacing anything, just doing the job that needs to be done.

  DateTime t;
  string name;
  for (int i = 0; i < listBox1.Items.Count; i++)
  {
  //first get the string beginning with the name ( Glenda ) to the end of the string
  name = listBox1.Items[i].Substring(listBox1.Items[i].IndexOf("=/>") + 3);
  //discard everything past the name from the first occurrence of "<", this leaves just the name
  name = name.Substring(0, name.IndexOf("<"));

  //now get the date part by extracting the string from pos 0 to the first occurrence of "<" in the listbox item string
  t = DateTime.Parse(listBox1.Items[i].Substring(0, listBox1.Items[i].IndexOf("<")));
  //Now add to list box 2
  listBox2.Items.Add(t.ToString("dd/MM/yy") + ","+ name);

  //or can be don in one go
  listBox2.Items.Add(((DateTime)t = DateTime.Parse(listBox1.Items[i].Substring(0, listBox1.Items[i].IndexOf("<")))).ToString("dd/MM/yy") + ","+ name));
  }
  }

Hi sorry back now

I have a listbox with lines looking like this: 05/9/11Glenda

And would like them to look like: 05/09/11,Glenda

If I can get a 6 digit date I can delete every thing else

also if I use:

string21.Insert(10, "a");

why does it go in at number 3 I'm a bit lost

Thanks in advance Mike

I would have thought that since the OP only wants the date part of the string it would be better to treat it as a date from the start.

If it is known that the start of the list item to the first "<" is in fact a date then anything from the "<" to the end of the line can be discarded so getting a substring of the date component eliminates the need to do a replace.

Casting the substring to a DateTime then formatting is gauranteed to return the date string in the final format  that you want regardless of region.

i.e.  dd/MM/yy, dd/MMM/yy, dd/MM/yyyy,  ddd d, MM, yyyy

can't get simpler than this

listBox1.Items.Add(((DateTime)t = DateTime.Parse(s[i].Substring(0, s[i].IndexOf("<")))).ToString("dd/MM/yy"));

I like simple, it it keeps programs simple and makes them more efficient with less overheads.

Cheers

Yes, there are several ways to do this without using regular expressions.

Perhaps, the easiest way of all is this one:

string[] s = new string[4];
          s[0] = "05/7/11John";
          s[1] = "05/11/11Sara";
          s[3] = "09/8/11Larry";
          s[4] = "05/11/11Glenda";

          //assuming that each item in the list box begins with the date you are wanting to move to listbox2
          //and the format is as per your example, then the following code will do what you are after.
          //notice that I am not inserting or replacing anything, just doing the job that needs to be done.

          DateTime t;
          for (int i = 0; i < s.Length; i++)
            {
            t = DateTime.Parse(s[i].Substring(0, s[i].IndexOf("<")));
            listBox2.Items.Addt.ToString("dd/MM/yy"));
            }

          //or this way
          DateTime t;

          for (int i = 0; i < s.Length; i++)
            listBox1.Items.Add((t = DateTime.Parse(s[i].Substring(0, s[i].IndexOf("<")))).ToString("dd/MM/yy"));


Unless of course using RegEx is essential for you to use, just a couple of alternatives

Hi Vulpes

I Have a ListBox that has 100 or so items.
some are like this:
05/7/11John
and some are like this
05/11/11Sara

But I all the single digit months to have a 0 in front so its like this:
05/07/11Tena
Can you see the difference in the date format, I need them to say 07 not 7 because when
I get to a month with 2 digits its goes wrong
I can delete the tags at the end, also the middle but need to set the date format so it
Reads 05/07/11 that way I have a solid base to start deleting

Using this only outputs the first item lots of times

string regExp1 = "(?\\d{1,2})/(?\\d{1})/(?(\\d{4}|\\d{2})).*";
string arr;
for (int a = 0; a < 1; a++)
{
        arr = listBox1.Items[a].ToString();
        if (Regex.IsMatch(arr, regExp1))
        {
                arr = arr.Insert(3, "0");
                arr = arr.Replace("", "");
                listBox2.Items.Add(arr);
        }

                       listBox2.Items.Add(arr);

}

ps That Expresso is cool tool thank you for guidance there.
Thanks Vulpes.
Mike.