title: Open a excel file and Add cell value
body: <p>I use C# &amp; Excel Intropt.dll for my project</p>
  
  <p>I want Open my xlsx file and adding a value (For Example "1") to All Of my cells in Sheet1.</p>
  
  <p>How can i achieve this?</p>
  
  <p>Like this:</p>
  
  <pre><code>12   14    19    22
  
  81   91    26    62
  </code></pre>
  
  <p>Result:</p>
  
  <pre><code>13   15    20    23
  
  82   92    27    63
  </code></pre>