Overriding Equals method in Structs

Question

I've looked for overriding guidelines for structs, but all I can find is for classes.

At first I thought I wouldn't have to check to see if the passed object was null, as structs are value types and can't be null. But now that I come to think of it, as equals signature is

public bool Equals(object obj)

it seems there is nothing preventing the user of my struct to be trying to compare it with an arbitrary reference type.

My second point concerns the casting I (think I) have to make before I compare my private fields in my struct. How am I supposed to cast the object to my struct's type? C#'s as keyword seems only suitable for reference types.

Thanks

Answer 1

Use the is operator:

public bool Equals(object obj)
{
  if (obj is MyStruct)
  {
    var o = (MyStruct)obj;
    ...
  }
}

Answer 2

struct MyStruct 
{
   public bool Equals(object obj) 
   {
       if (!(obj is MyStruct))
          return false;

       MyStruct mys = (MyStruct) obj;
       // compare elements here

   }

}

Answer 3

Adding to the existing answers.

You can still have nullable values if you append a ? after the struct name (this works for every value object)

int?

Casting is done also by calling (MyStructName)variableName