title: adding columns to datatable datatype nvarchar
body: <p>I declared a new dataset.
  Then added a datatable to it using the following command</p>
  
  <pre><code>DataTable newtable = ds.Tables.Add("returnresult");
  </code></pre>
  
  <p>now am trying to include two columns in this datatable with datatype "nvarchar".
  But the usual command for this does not accept nvarchar as a datatype</p>
  
  <pre><code> newtable.Columns.Add("UniqueID",typeof());
  </code></pre>
  
  <p>using this command does not show nvarchar in the datatypes.
  is there any other command to get nvarchar as the datatype for columns?</p>