C# Excel Add-Ins

我而家做緊EXCEL 2007 Add-Ins.但就出現左個問題.
因為我響EXCEL VBA果度就知點寫出黎.
但轉用C#就搵唔到對應既CODE.

咁我想REPLACE FORMULA.但呢個FORMULA就響PICTURE果度.
因為我D PICTURES係用FORMULAS去UPDATE個圖片.

而家我就想有時一次過UPDATE FORMULA入邊既野.

響EXCEL VBA就可以用Selection.Formula
但係我就唔知C# 係咩野?!
下邊我就係咁樣寫就可以CHECK到我D PICTURES出黎.但係就唔知點SHOW FORMULA出黎
如果有CHING知.可以講我知嘛.
Thanks

Excel.Worksheet activeWorksheet = Globals.ThisAddIn.Application.ActiveSheet;
foreach (Excel.Shape EachShape in activeWorksheet.Shapes)
{
//EachShape.Formula = "xxxxxxxx"
}