Question

For the current code:

 String currentPath = Directory.GetCurrentDirectory();

        OpenFileDialog op = new OpenFileDialog();
        op.InitialDirectory = currentPath;
        if (op.ShowDialog() == DialogResult.OK)
            currentPath = op.FileName;
        else
        {
            toolStripStatusLabel1.Text = "Failed to Load Workbook";
            toolStripStatusLabel1.Visible = true;
        }

        Workbook wb = new Workbook(excel.Workbooks.Open(currentPath));

I recieve the error:

System.Runtime.InteropServices.COMException was unhandled
Message=Retrieving the COM class factory for component with CLSID {00020819-0000-0000-C000-000000000046} failed due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG)).
Source=mscorlib
ErrorCode=-2147221164

All I want is a predefined workbook to add worksheets to

Answer 1

I suppose that in your code the fullname of Workbook is Microsoft.Office.Interop.Excel.Workbook, and that excel is an instance of Microsoft.Office.Interop.Excel.Application.

If this is the case your code can’t work because Workbook is an interface, and interfaces do not have constructors. You have to ask the excel application to create the workbooks for you, and in your case you have to simply write:

Workbook wb = excel.Workbooks.Open(currentPath); 

In a similar way, if you want to create a new empty workbook, you should write:

Workbook wb = excel.Workbooks.Add(System.Reflection.Missing.Value);