title: Formatting a column to use a phone number format in EPPlus
body: <p>I have phone numbers stored as a string of numbers, e.g.: 6028035615, but CAST them as integers when querying. I want to format the data in the cell in proper phone number format, such as (602) 803-5615 as Excel would. But how do I state the format type I want to use?
  If I use:</p>
  
  <pre><code>  objData.Columns.Add("HPhone", GetType(Integer))
    wshUS.Column(i).Width = 15 ' PhoneH
    wshUS.Column(i).Style.Numberformat.Format = "###-###-####"
  </code></pre>
  
  <p>or</p>
  
  <pre><code> wshUS.Column(i).Style.Numberformat.Format = "(###) ###-####"
  </code></pre>
  
  <p>a blank cell is shown as either -- in the former case or ()- in the latter.
  Is there a format type that I can put after the = to get phone numbers as Excel would?
  How would I use conditional formatting to overcome that problem?
  I am writing in VB.NET in codebehind for web pages.</p>