title: remove duplicate values from a list with multiple properties
body: <p>I have a list of <code>MyClass</code>:</p>
  
  <pre><code>class MyClass
  {
      public DateTime? DueDate;
      public string Desc;
      public Decimal Amount;
  }
  
  var sample = new List&lt;MyClass&gt;();
  </code></pre>
  
  <p>This is how sample data looks like :</p>
  
  <pre><code>DueDate     Desc    Amount 
  06-29-2015  ABC     100
  06-29-2015  DEF     200
  01-15-2015  ABC     100
  01-15-2015  DEF     200
  </code></pre>
  
  <p>Output I want in this format</p>
  
  <pre><code>DueDate     Desc    Amount 
  06-29-2015  ABC     100
              DEF     200
  01-15-2015  ABC     100
              DEF     200
  </code></pre>
  
  <p>So basically I would like to <strong>remove duplicate <code>DueDate</code> values</strong> but keeping its adjacent <code>Desc</code> &amp; <code>Amount</code> field values</p>
  
  <p>I tried this but it will remove values from adjacent column as well :</p>
  
  <pre><code>var test = sample.GroupBy(d =&gt; d.DueDate).Select(a =&gt; a.First()).ToList();
  </code></pre>
  
  <p>Any suggestions? </p>