title: How to add a tooltip for a datagrid header, where the header text is generated dynamically?
body: <p>I need to add a tooltip for a column header of a <code>DataGrid</code> (Silverlight 4). I will generate the number of columns and column header text dynamically.</p>
  
  <pre><code>GridColumnCreation(....)
  {
      IEnumerable allHeaderText = /* Linq query */; 
  }
  </code></pre>
  
  <p>How to use this collection to set a tooltip?</p>