C# Cannot implicitly convert one form to another form

Question

So i am trying to store my main form and open a new one however i get this error, here is the code:

I have this at form level

public static frmAddBook frmkeepBooks = null;



public frmMain()

{

    InitializeComponent();

    frmkeepBooks = this;

}

The error underlines "this" saying it "

Cannot inplicitly convert type Books.frmMain to Books.frmAddBook

"

Answer 1

Change the first line into:

public static frmMain frmkeepBooks = null;

The types should be equal (or in herited) and probably it is not.