How to extend String.Space similar to String.Empty in c#?

Question

I am trying to extend the System.String and add one more static field String.Space which represents a single space " " just like how Microsoft implemented String.Empty in the namespace Using System;. I am not able to implement this extension please help.

---

I wanted to implement a kind of field extension...

wanted the result like

Answer 1

You could have a static class like so;

public static class Strings
{
    public const string Space = " ";
}

And use it in your code like;

FullName = FirstName + Strings.Space + MiddleName + Strings.Space + LastName;

However, the ultimate goal is to make the code maintainable, be reasonably efficient and reduce the likelihood of errors. With that in mind, it's best to reduce the number of concatenations and supply just the values that are needed. To that end a simple format string would be a cleaner approach; (pre C#6);

FullName = string.Format("{0} {1} {2}", FirstName, MiddleName, LastName);

And if C#6+;

FullName = $"{FirstName} {MiddleName} {LastName}";

Why would you use those last two approaches? Well, it comes down to separation of concerns. Leave the string formatting to string.Format() and simply supply the values you need. You reduce the likelihood of errors by having fewer components in the mix, decrease maintenance overhead by the same and increase efficiency by reducing the number of strings involved to perform the concatenation.

EDIT

As for "Why doesn't c# support extension properties?", I'd extract a quote from Lindos Pechos's link from the C# language development team;

It was of course immediately obvious that the natural companion to extension methods is extension properties. It's less obvious, for some reason, that extension events, extension operators, extension constructors (also known as "the factory pattern"), and so on, are also natural companions. But we didn't even consider designing extension properties for C# 3; we knew that they were not necessary and would add risk to an already-risky schedule for no compelling gain.

Basically it boils down to "There wasn't a compelling need" for extension properties to allow you to create something like string.Space. Maybe in future versions.

Answer 2

Unfortunately the framework (v4.7 at the time of this writing) does not currently support extension properties/fields. See a good write up of this here "Why No Extension Properties?"

Which means you are limited to using an extension method. One such example:

namespace System.String
{
    public static class Extensions
    {
        public static string Space(this string s)
        {
            return " ";
        }
    }
}

Extension methods require an instance of an object. So it can be used as such:

// Returns " "
var space = "".Space();

Or

// Returns " "
var space = String.Empty.Space();

This falls into one of those "It's not pretty, but it works" categories.

Answer 3

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace StringFunctions.Extensions
{
   public static class StringExtensions 
    {
        public static readonly string Space = " ";

        public static string  Spacemethod(this string name)
        {
            return string.Concat(name," ");
        }
    }
}

in the place use the Alias name of class String. Like

using String = StringFunctions.Extensions.StringExtensions;

small string it's reserved word, so, it's throw Error.if you getting String.Space w=it's work entire places of class, other string function call like string.Empty Your functions call String.Space like this

using String = StringFunctions.Extensions.StringExtensions;
namespace StringFunctions
{
    class Program
    {
        static void Main(string[] args)
        {
            var t = String.Space;

        }

    }
}

Answer 4

I was able to do the following. You'll get a warning, but it compiles.

namespace System
{
    public static partial class String
    {
        public static string Space = " ";
    }
}

To call:

string sp = String.Space;