title: Initialize base class in .NET
body: <p>How do I go about if I need to initialize an object's base with existing object? For example, in this scenario:</p>
  
  <pre><code>public class A
  {
      public string field1;
      public string field2;
  }
  
  public class B : A
  {
      public string field3;
      public void Assign(A source)
      {
          this.base = source; // &lt;-- will not work, what can I do here?
      }
  }
  </code></pre>
  
  <p>Assign() method can, obviously assign values to the base class field-by-field, but isn't there a better solution? Since class B inherits from A, there must be a way to just assign A to the B.base</p>
  
  <p>In C++ this would be a trivial thing to do, but I can't seem to grasp how to do this in .NET</p>