String Interpolation In C#

Introduction

This article explains String Interpolation. As we know, Microsoft has announced many new features with Visual Studio 2015 Preview. It was announced on November 12, 2014, on the day of the Visual Studio Connect() event in New York, USA.

Visual C# 6.0, .NET Framework 4.6, and Roslyn Compiler have come with Visual Studio 2015 Preview. We will now explore String Interpolation. First, we should understand what String Interpolation means.

Figure 1.0

String Interpolation is nothing but a way to concatenate two or more strings together. As we are aware, in the previous version of .NET, we did string concatenation using the + (plus) operator. Sometimes for the same work, we have also used the String. Format method. Now we are pleased to hear that it became the old way to do string concatenation.

String Interpolation Before C# 6.0

Before discussing String Interpolation/concatenation with C# 6.0, let's discuss the old way to concatenate the string. As we know, we have two ways  to implement string interpolation with the previous version; they are

• C# 1.0
• C# 2.0
• C# 3.0
• C# 4.0 and
• C# 5.0 as well

Example

The old way to concatenate strings using the + operator.

See the following program written in Visual Studio 2013. It will run on any lower version of C# 6.0. 

using System;  
using System.Collections.Generic;  
using System.Linq;  
using System.Text;  
  
namespace StringInterpolation  
{  
    class StringInterpolation  
    {  
         public string FirstName { get; set; }  
         public string LastName { get; set; }  
         public string Email { get; set; }  
  
         static void Main(string[] args)  
         {  
             // In Visual Studio 2013  
  
             StringInterpolation si = new StringInterpolation();  
             si.FirstName = "Praveen";  
             si.LastName = "Kumar";  
             si.Email = "[email protected]";  
  
             Console.WriteLine("Name : "+ si.FirstName+" "+si.LastName+"\nEmail : "+si.Email);  
             Console.ReadLine();    
         }  
    }  
}  

Example

Old way to concatenate strings using a placeholder. 

using System;  
using System.Collections.Generic;  
using System.Linq;  
using System.Text;  
  
namespace StringInterpolation  
{  
    class StringInterpolation  
    {  
       public string FirstName { get; set; }  
       public string LastName { get; set; }  
       public string Email { get; set; }  
  
       static void Main(string[] args)  
       {  
           // In Visual Studio 2013  
  
            StringInterpolation si = new StringInterpolation();  
            si.FirstName = "Praveen";  
            si.LastName = "Kumar";  
            si.Email = "[email protected]";   
  
            Console.WriteLine(string.Format("Name : {0} {1}\nEmail : {2}", si.FirstName, si.LastName, si.Email));  
            Console.ReadLine();  
  
        }  
     }  
}  

String Interpolation in C# 6.0

Now we will describe the newest way to do string interpolation/concatenation with C# 6.0 that came with Visual Studio 2015, where Visual Studio 2015 is the latest IDE of the .NET Framework.

C# 6.0 is the newest version of C#. Microsoft added a very nice feature to accelerate our program code. Now we can put expressions directly in the string literal to show the values in an actual manner. In C# 6.0, we can easily specify various formats in our values. We can do the following.

• Place strings where we need them
• Specify a space after/before the string
• Use conditions

Another good thing is that we can now write a condition within the string literals with additional strings. Let's do it practically.

Example 

using System;  
using System.Collections.Generic;  
using System.Linq;  
using System.Text;  
using System.Threading.Tasks;  
  
namespace ConsoleApplication13  
{  
    class StringInterpolations  
    {  
         public string FirstName { get; set; }  
         public string LastName { get; set; }  
         public string Email { get; set; }  
         public int Age { get; set; }  

         static void Main(string[] args)  
         {  
              StringInterpolations si = new StringInterpolations();  
              si.FirstName = "Praveen";  
              si.LastName = "Kumar";  
              si.Age = 25;  
      
              // Putting String Where I need 
              Console.WriteLine("Name : \{si.FirstName} \{si.LastName}\nEmail : \{si.Email}\nAge :\{si.Age}");  
  
              // Putting Space After FirstName (10 pixel)
              Console.WriteLine("Name : \{si.FirstName,10} \{si.LastName}\nAge :\{si.Age :D2}");  
  
              //Putting Condition in string literal, If Age==25 it will display Age: Age is Over else Age in int value
              Console.WriteLine("Name : \{si.FirstName, 10} \{si.LastName}\nAge :\{si.Age==25?"" :"Age is Over"}");   
  
              Console.ReadLine();  
          }  
     }  
}  

Summary

In this article we learned the new String Interpolation with C# 6.0. We saw how to put the string where we need it, how to put a space after/before the string as well as how to set a condition.