Singleton and static classes are both design patterns in C# that are used to implement specific functionality in a software application. However, they have distinct differences in terms of their purpose, implementation, and use.
Singleton,
- The Singleton pattern ensures that a class has only one instance while providing a global point of access to this instance.
- Singleton classes are used when there needs to be a single instance of a class that is shared across the entire application.
- A Singleton class is instantiated using a private constructor and a static instance property. The instance property is used to access the single instance of the class.
Example
public sealed class Singleton {
private static Singleton instance = null;
private static readonly object padlock = new object();
Singleton() {}
public static Singleton Instance {
get {
lock(padlock) {
if (instance == null) {
instance = new Singleton();
}
return instance;
}
}
}
}
Static Classes
A static class is a class that can only contain static members and cannot be instantiated.
Static classes are used when a class is required to provide only a collection of utility or helper methods, and there is no need to create instances of the class.
Example
public static class Utilities {
public static int Add(int a, int b) {
return a + b;
}
public static int Subtract(int a, int b) {
return a - b;
}
}
In summary, the Singleton pattern is used to ensure that a class has only one instance and provides a global point of access to it, while the static class is used to create utility classes with only static members.