What is the C# equivalent to Java's isInstance()?

bool result = (obj is MyClass); // Better than using 'as'

The equivalent of Java’s obj.getClass().isInstance(otherObj) in C# is as follows:

bool result = obj.GetType().IsAssignableFrom(otherObj.GetType());

Note that while both Java and C# work on the runtime type object (Java java.lang.Class ≣ C# System.Type) of an obj (via .getClass() vs .getType()), Java’s isInstance takes an object as its argument, whereas C#’s IsAssignableFrom expects another System.Type object.

Depends, use is if you don't want to use the result of the cast and use as if you do. You hardly ever want to write:

if(foo is Bar) {
    return (Bar)foo;
}

Instead of:

var bar = foo as Bar;
if(bar != null) {
    return bar;
}

just off the top of my head, you could also do:

bool result = ((obj as MyClass) != null)

Not sure which would perform better. I'll leave it up to someone else to benchmark :)

Below code can be alternative to IsAssignableFrom.

parentObject.GetType().IsInstanceOfType(inheritedObject)

See Type.IsInstanceOfType description in MSDN.