String constructor

Usually a string constructor call is not needed. But the C# language has many string constructors. These create strings from characters and arrays.

One possible use for a string constructor is creating a string containing one char repeated many times. Another is converting a char array into a string.

Char array example

To begin, we show how to create a string from a char array. The string constructor in C# is useful for creating strings from various data sources.

using System;

// Part 1: create char array.
char[] charArray = new char[3];
charArray[0] = 'a';
charArray[1] = 'b';
charArray[2] = 'c';

// Part 2: create string from array.
string exampleString = new string(charArray);
Console.WriteLine(exampleString);
Console.WriteLine(exampleString == "abc");
abc
True

Repeated chars

Suppose we want to create a whitespace string with a space repeated 100 times. This is easy with the string constructor—no large string literal is needed.

using System;

// Create new string of repeated characters.
string exampleString = new string('a', 10);
Console.WriteLine(exampleString);
Console.WriteLine(exampleString == "aaaaaaaaaa");
aaaaaaaaaa
True

Char array, range

Suppose we have a char array, but want to create a string from just part of it. We can use another string constructor and specify and offset or a length.

using System;

// Create new string from range of characters in array.
char[] charArray = new char[6];
charArray[0] = 'a';
charArray[1] = 'B';
charArray[2] = 'c';
charArray[3] = 'D';
charArray[4] = 'e';
charArray[5] = 'F';

string exampleString = new string(charArray, 0, 3);
Console.WriteLine(exampleString);
Console.WriteLine(exampleString == "aBc");
aBc
True

Optimization

We can use the string constructors as an impressive optimization. Sometimes, we can entirely replace StringBuilder with a char array.

String constructors are occasionally useful. We used the 3 string constructors in C# that are not unsafe. And we found ways string conversions can be optimized.