String

Overview

C# String.Format() method formats strings in a desired format by inserting objects and variables with specified space and alignments into other strings. It is often used to also format strings into specific formats.

String.Format() manages formatting including the position, alignment, and format type. String.Format method has 8 overloaded formats to provide options to format various objects and variables that allows various variables to format strings. The simplest form of String.Format is the following:

String.Format("{index[,alignment][:formatString]}", **object**);

Where,

• index - The zero-based index of the argument whose string representation is to be included at this position in the string. If this argument is null, an empty string will be included at this position in the string.
• alignment - Optional. A signed integer that indicates the total length of the field into which the argument is inserted and whether it is right-aligned (a positive integer) or left-aligned (a negative integer). If you omit alignment, the string representation of the corresponding argument is inserted in a field with no leading or trailing spaces.
• If the value of alignment is less than the length of the argument to be inserted, alignment is ignored and the length of the string representation of the argument is used as the field width.
• formatString - Optional. A string that specifies the format of the corresponding argument's result string. If you omit formatString, the corresponding argument's parameterless ToString method is called to produce its string representation. If you specify formatString, the argument referenced by the format item must implement the IFormattable interface.

Alignment and spacing

By default, strings are right-aligned within their field if you specify a field width. To left-align strings in a field, you preface the field width with a negative sign, such as {0,-12} to define a 12-character right-aligned field.

Example

using System;
using System.Collections.Generic;

namespace ConsoleAppTest
{
    internal static class Program
    {
        private static void Main(string[] args)
        {
            var emp = new List<Employee>()
            {
                new Employee(1,"Vivek","CEO"),
                new Employee(2,"Deven","Designer"),
                new Employee(3,"Dhruv","Research")
        };
            System.Console.WriteLine("Employee List");
            Console.WriteLine($"{nameof(Employee.Id),-5}{nameof(Employee.Name),-10}{nameof(Employee.Dept)}");
            foreach (var item in emp)
            {
                Console.WriteLine($"{item.Id,-5}{item.Name,-10}{item.Dept,-10}");
            }

            Console.ReadKey();
        }
    }

    public class Employee
    {
        public int Id { get; set; }

        public string Name { get; set; }

        public string Dept { get; set; }

        public Employee(int id, string name, string dept)
        {
            Id = id;
            Name = name;
            Dept = dept;
        }
    }
}

Output

Employee List
Id   Name      Dept
1    Vivek     CEO
2    Deven     Designer
3    Dhruv     Research