C# 中 .NET 远程处理中实例的使用

Question

I have a problem regarding the usage of instances in C#. Can you please explain me the difference between the following 2 code lines:

public static DatabaseClass Instance { get; } = new DatabaseClass();

DatabaseClass _database = DatabaseClass.Instance;

Answer 1

The biggest difference is that this is declaration

public static DatabaseClass Instance { get; } = new DatabaseClass();

and this is usage

DatabaseClass _database = DatabaseClass.Instance;

You took 2 lines of code out of context. The true context is the classes that have these lines in. One class is most likely a Singleton

public class DatabaseClass 
{
    private DatabaseClass() {} // hide constructor

    public static DatabaseClass Instance { get; } = new DatabaseClass();
}

And another class has some method that calls the class above

public class SomeClass
{
    public static void DoSomething()
    {
        DatabaseClass _database = DatabaseClass.Instance;
        _database.PerformSomeOperation()
    }
}

By simply looking at the declaration, it is a common way to deal with singletons.

For your question the bottom line is that

line#1 is a declaration of the static property with default read-only value

line#2 is usage of that property