Notes, static arrays. This pattern is commonly used in C# programs and often useful. Static arrays can reduce allocations, which can improve performance.
First example. To start, we use a static integer array. The data shown is separate from the state of the object. The list of prime numbers is not affected by state.
Tip Your program can store static or constant data like these prime numbers for efficient access and use.
Detail This class contains a static int array that remains present throughout the lifetime of the program.
Detail The _primes array has an underscore at its start. This is a common pattern and helps show it is a field.
Note This array is initialized to 5 integers, and can be used without worrying about a class instance.
using System;
using System.Linq;
class Program
{
static void Main()
{
// Use the public method to test static array.
bool isWagstaff = NumberTest.IsWagstaffPrime(43);
Console.WriteLine(isWagstaff);
// Test static array again.
isWagstaff = NumberTest.IsWagstaffPrime(606);
Console.WriteLine(isWagstaff);
}
}
/// <summary>/// Contains static int array example./// </summary>
public static class NumberTest
{
/// <summary>/// This static array contains several Wagstaff primes./// </summary>
static int[] _primes = { 3, 11, 43, 683, 2731 };
/// <summary>/// Public method to test private static array./// </summary>
public static bool IsWagstaffPrime(int i)
{
return _primes.Contains(i);
}
}True
False
Example 2. Here we use a static string array to store type-specific information such as an array of dog breeds. This data is constant. It does not need to be frequently changed.
Detail We use the StringTest.Dogs property. The StringTest class contains an array of dog breed strings.
using System;
class Program
{
static void Main()
{
foreach (string dog in StringTest.Dogs)
{
Console.WriteLine(dog);
}
}
}
/// <summary>/// Contains static string array./// </summary>
public static class StringTest
{
/// <summary>/// Array of dog breeds./// </summary>
static string[] _dogs = new string[]
{
"schnauzer",
"shih tzu",
"shar pei",
"russian spaniel"
};
/// <summary>/// Get array of dog breeds publicly./// </summary>
public static string[] Dogs
{
get
{
return _dogs;
}
}
}schnauzer
shih tzu
shar pei
russian spaniel
List. A static List can store a variable number of elements in one location. The code can be used for much larger collections, and collections of varying sizes.
ArrayPool. An ArrayPool can make the reuse of arrays more powerful—we can specify minimum lengths required. And we can "rent" arrays to reduce conflicts.
A summary. We used static data structures such as int arrays and string arrays. These static collections are useful to access data that doesn't depend on an instance.
Dot Net Perls is a collection of tested code examples. Pages are continually updated to stay current, with code correctness a top priority.
Sam Allen is passionate about computer languages. In the past, his work has been recommended by Apple and Microsoft and he has studied computers at a selective university in the United States.
This page was last updated on Sep 12, 2023 (edit).
