title: Copy text from WPF DataGrid to Clipboard to Excel
body: <p>I have WPF DataGrid (VS2010 C#). I copied the data from DataGrid to Clipboard and write it to an Excel file. Below is my code.</p>
  
  <pre><code>dataGrid1.SelectAllCells();
  dataGrid1.ClipboardCopyMode = DataGridClipboardCopyMode.IncludeHeader;
  ApplicationCommands.Copy.Execute(null, dataGrid1);
  dataGrid1.UnselectAllCells();
  string path1 = "C:\\test.xls";
  string result1 = (string)Clipboard.GetData(DataFormats.CommaSeparatedValue);
  Clipboard.Clear();
  System.IO.StreamWriter file1 = new System.IO.StreamWriter(path1);
  file1.WriteLine(result1);
  file1.Close();
  </code></pre>
  
  <p>Everything works out OK except when I open the excel file it gives me two warning:</p>
  
  <blockquote>
    <p>"The file you are trying to open
    'test.xls' is in a different format
    than specified by the file extension.
    Verify that the file is not corrupted
    and is from a trusted source before
    opening the file. Do you want to open
    the file now?"</p>
    
    <p>"Excel has detected that 'test.xls' is
    a SYLK file, but cannot load it."</p>
  </blockquote>
  
  <p>But after I click through it, it still open the excel file OK and data are formated as it supposed to be. But I can't find how to get rid of the two warnings before the excel file is open.</p>