Check if object is NOT of type (!= equivalent for “IS”) - C#

Question

This works just fine:

    protected void txtTest_Load(object sender, EventArgs e)
    {
        if (sender is TextBox) {...}

    }

Is ther

Answer 1

If you use inheritance like:

public class BaseClass
{}
public class Foo : BaseClass
{}
public class Bar : BaseClass
{}

... Null resistant

if (obj?.GetType().BaseType != typeof(Bar)) { // ... }

or

if (!(sender is Foo)) { //... }