title: Create class instance from string in dartlang
body: <p>I have created this class </p>
  
  <pre><code>class Opacity {
    String a,b,c;
  
    Opacity({this.a, this.b,this.c});
  }
  </code></pre>
  
  <p>And I'm trying to dynamically create an instance of this class only using strings and an hashmap for arguments.</p>
  
  <pre><code>String type = "Opacity";
  List&lt;String&gt; args = {'a': 'a', 'b': 'b','c': 'c'}
  </code></pre>
  
  <p>And I have one constraint, I can't modify the <code>Opacity</code> class.</p>
  
  <p>For creating the instance I thought about using reflection to dynamically create the class from string but I can't figure out how to pass the arguments dynamically.</p>