How to convert an integer to string with padding zero in C#?

There are several ways to convert an integer to a string in C#.

PadLeft − Returns a new string of a specified length in which the beginning of the current string is padded with spaces or with a specified Unicode character

ToString − Returns a string that represents the current object.

String Interpolation − The $ special character identifies a string literal as an interpolated string. This feature is available starting with C# 6.

Example using string padding−

Example

 Live Demo

using System;
namespace DemoApplication{
   class Program{
      public static void Main(){
         int number = 5;
         Console.WriteLine("Number: {0}", number);
         var numberString = number.ToString().PadLeft(4, '0');
         Console.WriteLine("Padded String: {0}", numberString);
         Console.ReadLine();
      }
   }
}

Output

The output of the above code is

Number: 5
Padded String: 0005

Example using explicit form −

Example

 Live Demo

using System;
namespace DemoApplication{
   class Program{
      public static void Main(){
         int number = 5;
         Console.WriteLine("Number: {0}", number);
         var numberString = number.ToString("0000");
         Console.WriteLine("Padded String: {0}", numberString);
         Console.ReadLine();
      }
   }
}

Output

The output of the above code is

Number: 5
Padded String: 0005

Example using short form format specifier −

Example

 Live Demo

using System;
namespace DemoApplication{
   class Program{
      public static void Main(){
         int number = 5;
         Console.WriteLine("Number: {0}", number);
         var numberString = number.ToString("D4");
         Console.WriteLine("Padded String: {0}", numberString);
         Console.ReadLine();
      }
   }
}

Output

The output of the above code is

Number: 5
Padded String: 0005

Example using string interpolation−

Example

 Live Demo

using System;
namespace DemoApplication{
   class Program{
      public static void Main(){
         int number = 5;
         Console.WriteLine("Number: {0}", number);
         var numberString = $"{number:0000}";
         Console.WriteLine("Padded String: {0}", numberString);
         Console.ReadLine();
      }
   }
}

Output

The output of the above code is

Number: 5
Padded String: 0005