C# comparing multiple type

Question

I have the following legacy code:

if (isOnMainWindow
    || (win.GetType() != typeof(winInputBox)
    && win.GetType() != typeof(winMessage)
    && win.GetType() != typeof(winMsgBox)
    && win.GetType() != typeof(winAbout))
    ApplicationCommands.Close.Execute(null, win);

This looks horrible. Is there a way to compare multiple types of an objects as in my case?

Answer 1

There is nothing that can do just what you want, but why not use a simpler syntax:

if (!(win is winInputBox) && !(win is winMessage) && !(win is winMsgBox) && !(win is winAbout)) ApplicationCommands.Close.Execute(null, win);

Alternatively, you can use a method to make your life easier:

public static IsNotOneOf(object obj, params Type[] types)
{
    foreach (var type in types)
    {
        if (type.IsAssignableFrom(obj.GetType()) return false;
    }

    return true;
}

And you can use it as this:

if (IsNotOneOf(win, typeof(winInputBox), typeof(winMessage), typeof(winMsgBox), typeof(winAbout)) ApplicationCommands.Close.Execute(null, win);