Unhide all Hidden Excel Columns Without Individual Iteration

Question

Can all hidden columns in an Excel worksheet be revealed?

This is the code I use to reveal every hidden row. I don't want to repeatedly cycle through and verify how many columns are being used in the range.

foreach (string filePath in _allFiles)
        {
            try
            {
                _wb = _app.Workbooks.Open(filePath, ReadOnly: false);

                foreach (Excel.Worksheet ws in _wb.Worksheets)
                {
                    try
                    {
                        string abc = ws.Name;
                        ws.ShowAllData(); /* needs try catch 'cause if no filters are applied, it will throw an exception */
                    }
                    catch (Exception ex)
                    {   }
                }
            }
            catch (Exception ex2)
            {   }
            finally
            {
                _wb.Save();
                _wb.Close();
                //_app.Quit();
                //Marshal.ReleaseComObject(_app);
            }
        }
        _app.Quit();
        Marshal.ReleaseComObject(_app);

Answer 1

I discovered that the best way to figure out how to perform a given activity is to develop a VBA macro of the procedure. The macro should then be converted into interop calls.

What I've discovered is that the columns and rows collection can be called for each workbook and set (as in the VBA macro) as follows:

Columns.EntireColumn.Hidden = False
Rows.EntireRow.Hidden = False

You still have to iterate between the workbooks and call the appropriate C# interop methods.