In this source code example, we show you different ways to concatenate string in C# with an example.

Immutable strings can be added using the + operator or the Concat method. They form a new string which is a chain of all concatenated strings. Mutable strings have the Append method which builds a string from any number of other strings.

C# String Concatenation Example

The example creates five sentences by concatenating strings.

using System;
using System.Text;

class Example {
    static void Main() {
        
        string s1 = "Source";
        string s2 = " Code ";
        string s3 = "Examples";
        
        // concatenate string using + operator
        Console.WriteLine(s1 + s2 + s3);
        
        // concatenate string using Concat method
        Console.WriteLine(string.Concat(string.Concat(s1, s2), s3));
        
        var sb = new StringBuilder();
        sb.Append(s1);
        sb.Append(s2);
        sb.Append(s3);
        
        Console.WriteLine(sb);
         
        Console.WriteLine("{0}{1}{2}", s1, s2, s3);
        Console.WriteLine($"{s1}{s2}{s3}");
    }
}

Output:

Source Code Examples

Source Code Examples

Source Code Examples

Source Code Examples

Source Code Examples

A new string is formed by using the + operator:

        // concatenate string using + operator
        Console.WriteLine(s1 + s2 + s3);

The Concat method concatenates two strings. The method is a static method of the System.String class.

        // concatenate string using Concat method
        Console.WriteLine(string.Concat(string.Concat(s1, s2), s3));

A mutable object of the StringBuilder type is created by calling the Append method three times:

        var sb = new StringBuilder();
        sb.Append(s1);
        sb.Append(s2);
        sb.Append(s3);
        
        Console.WriteLine(sb);

A string is formed with string formatting:

        Console.WriteLine("{0}{1}{2}", s1, s2, s3);

Finally, the strings are added with the interpolation syntax:

        Console.WriteLine($"{s1}{s2}{s3}");