title: Cannot convert type via a reference conversion, boxing conversion, unboxing conversion, wrapping conversion, or null type conversion
body: <p>In C#, if I have a parameter for a function where the parameter type is of an interface, how do a pass in an object that implements the interface.</p>
  
  <p>Here is an example:</p>
  
  <p>The parameter for a function is as follows:</p>
  
  <pre><code>List&lt;ICustomRequired&gt;
  </code></pre>
  
  <p>The list that I already have is as follows:</p>
  
  <pre><code>List&lt;CustomObject&gt; exampleList
  </code></pre>
  
  <p><code>CustomObject</code> inherits from the <code>ICustomRequired</code> interface</p>
  
  <p>What is the correct syntax to pass the <code>exampleList</code> as a parameter?</p>
  
  <p>This is how I thought to do the above task:</p>
  
  <pre><code>exampleList as List&lt;ICustomRequired&gt;
  </code></pre>
  
  <p>However I am getting the following error:</p>
  
  <blockquote>
    <p>Cannot convert type via a reference conversion, boxing conversion,
    unboxing conversion, wrapping conversion, or null type conversion</p>
  </blockquote>
  
  <p>Thanks</p>