Name does not exist in the current context

Question

In the code below, the line

XlApp.ScreenUpdating = false;

throws the error: The name XlApp.ScreenUpdating does not exist in the current context

How can I fix it?

I can however refer within the same scope to Workbooks and Worksheets of the Excel App XlApp

If I include the line XlApp.ScreenUpdating = false; inside a method in the same class it works fine. But I need at the top to apply to all methods in the class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Office.Interop.Excel;

namespace Sample
{

public class EW: EWrapper
{


    static Microsoft.Office.Interop.Excel.Application XlApp = (Microsoft.Office.Interop.Excel.Application)System.Runtime.InteropServices.Marshal.GetActiveObject("Excel.Application");

    XlApp.ScreenUpdating = false; //throws error


    Worksheet Inventory_pos = XlApp.Workbooks["Inventory.xlsm"].Worksheets["pos"]; //no error
  

Answer 1

Thank you Castorix31!

Answer 2

You can put it in the Constructor, like :

public class EW: EWrapper
{
    public Microsoft.Office.Interop.Excel.Application XlApp = null;
    public EW()
    {
        if (Process.GetProcessesByName("excel").Count() > 0)
        {
            XlApp = Marshal.GetActiveObject("Excel.Application") as Microsoft.Office.Interop.Excel.Application;
            XlApp.ScreenUpdating = false;
        }
    }
}