Can a Base Class Object Be Assigned to a Derived Class Reference in C#?

Assign base class object to derived class reference in C#

In C#, can I use explicit type conversion to assign a base class object to a derived class reference? Attempting to do this will result in a runtime error.

Explanation

You cannot directly assign a base class object to a derived class reference. This is because a derived class reference assumes that it points to an instance of the derived class, not a base class object. Assigning a base class object to a derived class reference can lead to inconsistent behavior and unexpected results.

Example

Consider the following code:

<code class="language-csharp">object o = new object();
string s = (string)o;
int i = s.Length;</code>

Attempting to access the Length property of the string variable s will result in an exception because s is actually an object, not a string.

In order to achieve conversion between base and derived classes, consider implementing a method that creates an appropriate derived type instance based on the base type. Alternatively, re-evaluate the inheritance hierarchy to eliminate the need for this conversion.

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