title: Unable to assign FormulaArray on a selected Excel Range object in C#
body: <p>My C# code manipulates Excel Ranges using Microsoft.Office.Interop.Excel library. I need to assign a Formula Array to a selected Range. I've tried a variety of methods recommended online, including Microsoft recommendations, but so far was unable to make it work properly.</p>
  
  <p>I observe 2 issues:</p>
  
  <p>Issue 1. 
  Assignment looks fine on surface: it does not fail, cell objects in the range show .ArrayFormula property assigned, on the spreadsheet formula in every cell appears in curly brackets. However, the Formula Array is actually disjointed: each cell in the range can be changed separately, which normal Formula Array would not permit. It behaves as if every cell had its own, single-cell Formula Array, independent from others. Regardless of my best efforts, this is ALWAYS the case. 
  Is there actually a properly working solution for this issue?</p>
  
  <p>Issue 2.
  My Array Formula contains a reference to another Range (Range A), which I need to refer to in R1C1 style. I need Array Formula in every cell in the target Range point to the same Range A. Somehow I always end up with every cell in target Range having its own version of the formula, referring to shifted "Range A" area. How do I make the reference stay in place, regardless of a cell?</p>
  
  <p>N.B. You may assume that Issue 2 is causing Issue 1, but this is not the case: for example, when array formula is simple, like "=SIN(1)", the Issue 1 still occurs.</p>
  
  <p>I would really appreciate any WORKING suggestions. Thanks a lot in advance.</p>