title: Error "CS0104: 'DataType' is an ambiguous reference between 'System.ComponentModel.DataAnnotations.DataType' and 'CarlosAg.ExcelXmlWriter.DataType"
body: <p>I am getting this error:</p>
  
  <blockquote>
    <p>"CS0104: 'DataType' is an ambiguous reference between
    'System.ComponentModel.DataAnnotations.DataType' and
    'CarlosAg.ExcelXmlWriter.DataType'"</p>
  </blockquote>
  
  <p>while running an ASP.NET 4.0 application. Can any one help me on this issue?</p>