C# – How to a static class derive from an object

c++oop

I am trying to inherit a non-static class by a static class.

public class foo
{ }

public static class bar : foo
{ }

And I get:

Static class cannot derive from type.
Static classes must derive from
object.

How can I derive it from object?

The code is in C#.

Best Solution

There's no value in deriving static classes. The reasons to use inheritance are:

Polymorphism
Code reuse

You can't get polymorphism with static classes, obviously, because there is no instance to dynamically dispatch on (in other words, it's not like you can pass a Bar to a function expecting a Foo, since you don't have a Bar).

Code reuse is easily solved using composition: give Bar a static instance of Foo.

Related Solutions

C# – Calling the base constructor in C#

Modify your constructor to the following so that it calls the base class constructor properly:

public class MyExceptionClass : Exception
{
    public MyExceptionClass(string message, string extrainfo) : base(message)
    {
        //other stuff here
    }
}

Note that a constructor is not something that you can call anytime within a method. That's the reason you're getting errors in your call in the constructor body.

C# – How to cast int to enum

From an int:

YourEnum foo = (YourEnum)yourInt;

From a string:

YourEnum foo = (YourEnum) Enum.Parse(typeof(YourEnum), yourString);

// The foo.ToString().Contains(",") check is necessary for enumerations marked with an [Flags] attribute
if (!Enum.IsDefined(typeof(YourEnum), foo) && !foo.ToString().Contains(","))
{
    throw new InvalidOperationException($"{yourString} is not an underlying value of the YourEnum enumeration.")
}

Update:

From number you can also

YourEnum foo = (YourEnum)Enum.ToObject(typeof(YourEnum) , yourInt);

Best Solution

Related Solutions

C# – Calling the base constructor in C#

C# – How to cast int to enum

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