title: DataView.ToTable is not case-insensitive
body: <p>I am trying to create a DataView that has distinct rows that are case insensitive.</p>
  
  <p>The  project is a list of XML files where the name is a concatenation of 4 user typed fields separated with a <code>_</code> character.  These are read and put into a string array with the <code>Split('_')</code> method and the initial table is created.  What we want is 4 separate listboxes with the unique case insensitive text strings in them so the user can select any of the file combinations. The user can set a sort and filter on any or all of the 4 sections.</p>
  
  <pre><code>AAAA_BBBB_CCCC_1.xml
  
  aaaa_bBBB_cccc_2.xml
  
  Aaaa_BBbB_CcCC_3.xml
  
  DDDD_EEEE_FFFF_1.xml
  
  dddd_eeee_ffff_2.xml
  
  DDdD_EeEE_fFFF_3.xml
  </code></pre>
  
  <p>Should produce these 4 listboxes with this data in them</p>
  
  <pre><code>AAAA  BBBB  CCCC   1
  
  DDDD  EEEE  FFFF   2
  
                     3
  </code></pre>
  
  <p>Code for loading the first listbox</p>
  
  <pre><code>    DataView dv = _dtMasterDataBase.DefaultView;
  _dtNames = dv.ToTable(true, new[] {Column1, Column2, Column3, Column4});
  dv = _dtColumn1.DefaultView;
  
  dv.Sort = ...a string containing 1-4 columns in Asc or Desc
  dv.RowFilter = ...a string containing filters for 1-4 columns
  
  _dtColumn1= dv.ToTable(true, new[] {Column1});
  DataView dvColumn1 = _dtColumn1.DefaultView
  
  ListBoxColumn1.DataSource = dvColumn1;
  ListBoxColumn1.DisplayMember = "Column1";
  </code></pre>
  
  <p>What shows up in the first listbox is</p>
  
  <p>AAAA</p>
  
  <p>aaaa</p>
  
  <p>Aaaa</p>
  
  <p>DDDD</p>
  
  <p>DDdD</p>