Product serial number manipulation

[Borresen77]

Good day all, I am working on a project and i am trying to find a way to manipulate a product serial number that is read from a combobox and written to a String which is then applied to a print of a Label. The Label media was changed and now the area is alot smaller so i need to reduce the serial number printed to 4 characters as apposed to 10. Here is an example, in the combobox you would select 1234A00123 all i want to be pulled from the serial number for this variable is A123, so the Alphabet and last 3 characters of the serial. Is there a specific way the cut this when it is being read into a string? this is the code used to pull the selected serial number. ( string text = comboBoxPartNumbers.SelectedItem.ToString(); ) Any advice is welcome.

 

[jmcilhinney]

Firstly, the items in the ComboBox already are strings so, while it's not strictly wrong, it's less appropriate to call ToString on them. That's generally to create a string from something that isn't. If the object is a string already but you're accessing it via an object reference then the more appropriate option is to cast:

var text = (string) comboBoxPartNumbers.SelectedItem;

That said, if what you want is the text displayed for the SelectedItem then you can just use the Text property, which is already type string:

var text = comboBoxPartNumbers.Text;

 

[jmcilhinney]

As for the question, does the letter appear in the same place in the text every time? If so then you could do this:

var text = comboBoxPartNumbers.Text;

text = text[4] + text.Substring(7, 3);

or this:

text = text.Substring(4, 1) + text.Substring(7, 3);

or other variations like that.

 

[Skydiver]

Assuming that you have the text using this:

var text = comboBoxPartNumbers.Text;

Then to get the first alphabetic character, you would do something like:

var firstAlphaChar = text.First(ch => Char.IsLetter(ch));

This invokes the LINQ extension method First() which will return the first character that satisfies the condition Char.IsLetter().

To get the last 3 "digits" of the text, we just get the last 3 characters of the text (taking advantage of C# 8.0's indexes and ranges):

var lastThreeChars = text[^3..];

Then we just put it all together:

var abbreviatedText = firstAlphaChar + lastThreeChars;

Here's a sample program:

using System;
using System.Linq;

namespace ConsoleApp8
{
    class Program
    {
        static void Main(string[] args)
        {
            var text = "1234A00123";

            var firstAlphaChar = text.First(ch => char.IsLetter(ch));
            var lastThreeChars = text[^3..];
            var abbreviatedText = firstAlphaChar + lastThreeChars;
            Console.WriteLine($"{abbreviatedText}");
        }
    }
}