String append

Strings can be appended one after another. There are no Append or Add methods on the string type. And strings must be copied, not modified in-place.

We provide a quick reference for how to add one string on the end to an existing string. The concat operator can be used.

Example

Many programmers are familiar with appending strings, but the string type lacks an "Append" method. Instead, it is best to use the plus operator on different instances of strings.

using System;

string value = "cat ";

// Step 1: append a word to the string.
value += "and ";
Console.WriteLine(value);

// Step 2: append another word.
value += "dog";
Console.WriteLine(value);
cat and 
cat and dog

Example 2

Let's look at how you can append string values—and append multiple values at once. This example creates a two-line string, using 3 string variables.

using System;

string value1 = "One";
string value2 = "Two";

// Append newline to string and also string.
value1 += Environment.NewLine + value2;
Console.WriteLine(value1);
One
Two

Internals

When you compile one of the above C# programs, the compiler will transform the + operators into calls to String.Concat. You can use String.Concat for the same effect.

We looked at how you can append strings. It is easiest to use the + operator. And we can append to an existing variable with the += operator.