String.Intern(String) Method

Definition

Retrieves the system's reference to the specified String.

public static string Intern (string str);

Parameters

str
String

A string to search for in the intern pool.

Returns

The system's reference to str, if it is interned; otherwise, a new reference to a string with the value of str.

Exceptions

str is null.

Examples

The following example uses three strings that are equal in value to determine whether a newly created string and an interned string are equal.

// Sample for String.Intern(String)
using System;
using System.Text;

class Sample
{
    public static void Main()
    {
        string s1 = "MyTest";
        string s2 = new StringBuilder().Append("My").Append("Test").ToString();
        string s3 = String.Intern(s2);
        Console.WriteLine($"s1 == {s1}");
        Console.WriteLine($"s2 == {s2}");
        Console.WriteLine($"s3 == {s3}");
        Console.WriteLine($"Is s2 the same reference as s1?: {(Object)s2 == (Object)s1}");
        Console.WriteLine($"Is s3 the same reference as s1?: {(Object)s3 == (Object)s1}");
    }
}
/*
This example produces the following results:
s1 == MyTest
s2 == MyTest
s3 == MyTest
Is s2 the same reference as s1?: False
Is s3 the same reference as s1?: True
*/

Remarks

For more information about this API, see Supplemental API remarks for String.Intern.

Applies to

Product Versions
.NET Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 2.0, 2.1

See also