title: Excel Worksheet Modifying Current Sheet C#
body: <p>Is there anyway that you can modify an already opened worksheet in Excel. Their MSDN page gives you what is below. This adds a new workbook and worksheet everytime. I have the code opening and existing worksheet, and I just want it to replace the value in the cell and the close. Any help is greatly appreciated.</p>
  
  <pre><code>using Excel = Microsoft.Office.Interop.Excel; //Excel Reference
  
   public virtual Object ActiveSheet { get; set; }
  
   private void button15_Click(object sender, EventArgs e)//Generate Model and Part Numbers
      {
          Excel.Application oXL;
          Excel._Workbook oWB;
          Excel._Worksheet oSheet;
  
          //Start Excel and get Application object.
          oXL = new Excel.Application();
          oXL.Visible = true;
  
          //Get a new workbook.
          oWB = (Excel._Workbook)(oXL.Workbooks.Add(Missing.Value));
          oSheet = (Excel._Worksheet)oWB.ActiveSheet;  
          oSheet.Cells[6, 4] = "0"; //Change Value in Cell in Excel Cell Location [y-axis, x-axis]
       }
  </code></pre>