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• Upcasting is an operation that creates a base class reference from a subclass reference. (subclass -> superclass) (i.e. Manager -> Employee)
• downcasting is an operation that creates a subclass reference from a base class reference. (superclass -> subclass) (i.e. Employee -> Manager)

In your case

Employee emp = (Employee)mgr; //mgr is Manager

you are doing an upcasting.

An upcast always succeeds unlike a downcast that requires an explicit cast because it can potentially fail at runtime.(InvalidCastException).

C# offers two operators to avoid this exception to be thrown:

Starting from:

Employee e = new Employee();

First:

Manager m = e as Manager; // if downcast fails m is null; no exception thrown

Second:

if (e is Manager){...} // the predicate is false if the downcast is not possible 

Warnign: When you do an upcast you can only access to the superclass' methods, properties etc...

• Upcasting is an operation that creates a base class reference from a subclass reference. (subclass -> superclass) (i.e. Manager -> Employee)
• Downcasting is an operation that creates a subclass reference from a base class reference. (superclass -> subclass) (i.e. Employee -> Manager)

In your case

Employee emp = (Employee)mgr; //mgr is Manager

you are doing an upcasting.

An upcast always succeeds unlike a downcast that requires an explicit cast because it can potentially fail at runtime.(InvalidCastException).

C# offers two operators to avoid this exception to be thrown:

Starting from:

Employee e = new Employee();

First:

Manager m = e as Manager; // if downcast fails m is null; no exception thrown

Second:

if (e is Manager){...} // the predicate is false if the downcast is not possible 

Warning: When you do an upcast you can only access to the superclass' methods, properties etc...

1. Upcasting is an operation that creates a base class reference from a subclass reference. (subclass -> superclass) (i.e. Manager -> Employee)
2. downcasting is an operation that creates a subclass reference from a base class reference. (superclass -> subclass) (i.e. Employee -> Manager)

An upcast always succeeds unlike a downcast that requires an explicit cast because it can potentially fail at runtime.(InvalidCastException).

C# offers two operators to avoid this exception to be thrown:

Employee e = new Employee();
Manager m = e as Manager; // m is null; no exception thrown

or

if (e is Manager){...}

When you do an upcast you can only access to the superclass' methods, properties etc...

• Upcasting is an operation that creates a base class reference from a subclass reference. (subclass -> superclass) (i.e. Manager -> Employee)
• downcasting is an operation that creates a subclass reference from a base class reference. (superclass -> subclass) (i.e. Employee -> Manager)

In your case

Employee emp = (Employee)mgr; //mgr is Manager

you are doing an upcasting.

An upcast always succeeds unlike a downcast that requires an explicit cast because it can potentially fail at runtime.(InvalidCastException).

C# offers two operators to avoid this exception to be thrown:

Starting from:

Employee e = new Employee();

First:

Manager m = e as Manager; // if downcast fails m is null; no exception thrown

Second:

if (e is Manager){...} // the predicate is false if the downcast is not possible 

Warnign: When you do an upcast you can only access to the superclass' methods, properties etc...

1. Upcasting is an operation that creates a base class reference from a subclass reference. (subclass -> superclass) (i.e. Manager -> Employee)
2. downcasting is an operation that creates a subclass reference from a base class reference. (superclass -> subclass) (i.e. Employee -> Manager)

An upcast always succeeds unlike a unlike a downcast that requires an explicit cast because it can potentially fail at runtime.(InvalidCastException).

C# offers two operators to avoid this exception to be thrown:

Employee e = new Employee();
Manager m = e as Manager; // m is null; no exception thrown

or

if (e is Manager){...}

When you do an upcast you can only access to the superclass' methods, properties etc...

1. Upcasting is an operation that creates a base class reference from a subclass reference. (subclass -> superclass) (i.e. Manager -> Employee)
2. downcasting is an operation that creates a subclass reference from a base class reference. (superclass -> subclass) (i.e. Employee -> Manager)

An upcast always succeeds unlike a downcast that requires an explicit cast because it can potentially fail at runtime.(InvalidCastException).

C# offers two operators to avoid this exception to be thrown:

Employee e = new Employee();
Manager m = e as Manager; // m is null; no exception thrown

or

if (e is Manager){...}

When you do an upcast you can only access to the superclass' methods, properties etc...