Removing Lines from the textBox.

Question

I am Reading data from serialport. I just want 40 lines to appear in the textbox.

How I can erase lines older lines to make Place for new lines?

I tried the following code:

     int numOfLines = 40; 
    var lines = this.textBox1.Lines;
    var newLines = lines.Skip(numOfLines);
    this.textBox1.Lines = newLines.ToArray();

But it gives me error, saying that " 'string[]' does not contain a definition for 'Skip' and no extension method 'Skip' accepting a first argument of type 'string[]' could be found".

Didn't you just asked the same some minutes ago? Add `using System.Linq;` to your class — Pikoh, Apr 29 '16 at 09:04
@Pikoh Thanks :) I deleted that and came with a new question o show what code I have tried. "using System.Linq" did not work. same problem arise. — user6203007, Apr 29 '16 at 09:14
Do you have a reference in your proyect to `System.Core`? What .net platform target do you have? — Pikoh, Apr 29 '16 at 09:21

score 0 · Answer 1 · edited May 23 '17 at 10:28

0

I think you have forgotten to add using System.Linq; directive

P.S. if you want last 40 lines to be appear, you can use approach described in this question: Using Linq to get the last N elements of a collection?

edited May 23 '17 at 10:28

Community

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answered Apr 29 '16 at 09:05

hmnzr

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`Take(n)` will give first n-elements. But not last n. – Leonid Malyshev Apr 29 '16 at 09:08
@LeonidMalyshev sorry, missed that question, will fix my post – hmnzr Apr 29 '16 at 09:10
same problem. saying that "using directive is unnecessary" – user6203007 Apr 29 '16 at 09:27
@user6203007 "using directive is unnecessary"..are you using Mono? – Pikoh Apr 29 '16 at 09:31

score 0 · Answer 2 · answered Apr 29 '16 at 09:07

0

You need to add a reference to Linq:

using System.Linq;

answered Apr 29 '16 at 09:07

Ash

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same problem. saying that "using directive is unnecessary" – user6203007 Apr 29 '16 at 09:28
Can you send me all the using directives in that files. Also what framework are you working with? – Ash Apr 29 '16 at 09:55
using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; using System.IO.Ports; using System.IO; using System.Text.RegularExpressions; – user6203007 Apr 29 '16 at 10:03
try this and tell me what happens....................... var newLines = System.Linq.Enumerable.Skip(lines, numOfLines); – Ash Apr 29 '16 at 10:25
It says the namespace name 'Linq' does not exist in the namespace 'System'. – user6203007 Apr 29 '16 at 10:37
1

@user6203007...i've already told you, add a reference to System.Core in your project – Pikoh Apr 29 '16 at 10:44

Pikoh · Answer 3 · 2016-04-29T11:41:08.230

Skip is a extension method of LINQ. You must add a reference to System.Core in your project, and in case it's needed a using System.Linq; directive

Edit

As you seem to be "unable" to use LINQ, here is a non-LINQ solution (just as an experiment of reinventing the wheel):

Extension Methods

public static class ExtMeth
{
    public static IEnumerable<string> SkipLines(this string[] s, int number)
    {
        for (int i = number; i < s.Length; i++)
        {
            yield return s[i];
        }
    }

    public static string[] ToArray(this IEnumerable<string> source)
    {
        int count = 0;
        string[] items = null;
        foreach (string it in source)
        {
            count++;
        }
        int index = 0;
        foreach (string item in source)
        {
            if (items == null)
            {
                items = new string[count];
            }
            items[index] = item;
            index++;
        }
        if (count == 0) return new string[0];
        return items;
    }
}

Usage

this.textBox1.Lines = this.textBox1.Lines.SkipLines(2).ToArray();

Removing Lines from the textBox.

3 Answers3