I want to add a formula as shown in the third component. When i remove the "=" everything works. But for adding a formula to excel, you need the "="... When I add the "=", the program doesn't work anymore... Then I receive the error: System.Runtime.InteropServices.COMException was unhandled HResult=-2146827284 Message=Exception of HRESULT: 0x800A03EC

Any ideas?

Thank you

```
static void Main(string[] args)
{
//seed
var listComponents = new List<Component>
{
new Component() {Name = "Vc1", Cell = "A1"},
new Component() {Name = "Vc2", Cell="B1"},
new Component() {Name = "Nv", Cell="A2",Calculation = "=((A1+B1)/2)/0,1"}
};
//program
//create excel object, workbook and worksheet
object misValue = System.Reflection.Missing.Value;
var excelapp = new Excel.Application();
Excel.Workbook newWorkbook = excelapp.Workbooks.Add();
Excel._Worksheet worksheet = (Excel.Worksheet) excelapp.ActiveSheet;
excelapp.Visible = false;
//cycle through components
foreach (var component in listComponents)
{
if (component.Calculation != null)
{
Excel.Range rng = worksheet.Range[component.Cell];
rng.Formula = component.Calculation;
String formula = rng.Formula;
Console.WriteLine(formula);
}
}
newWorkbook.Close(false, misValue, misValue);
excelapp.Quit();
Console.ReadLine();
}
```