How to merge two Excel workbook into one workbook in C#?

Question

Let us consider that I have two Excel files (Workbooks) in local. Each Excel workbook is having 3 worksheets.

Lets say WorkBook1 is having Sheet1, Sheet2, Sheet3

Answer 1

Here's a working sample that joins two books into a new one, hope it will give you an idea:

using System;
using Excel = Microsoft.Office.Interop.Excel;
using System.Reflection; 


namespace MergeWorkBooks
{
    class Program
    {
        static void Main(string[] args)
        {
            Excel.Application app = new Excel.Application();

            app.Visible = true;
            app.Workbooks.Add("");
            app.Workbooks.Add(@"c:\MyWork\WorkBook1.xls");
            app.Workbooks.Add(@"c:\MyWork\WorkBook2.xls");


            for (int i = 2; i <= app.Workbooks.Count; i++)
            {
                int count = app.Workbooks[i].Worksheets.Count;

                app.Workbooks[i].Activate();
                for (int j=1; j <= count; j++)
                {
                    Excel._Worksheet ws = (Excel._Worksheet)app.Workbooks[i].Worksheets[j];
                    ws.Select(Type.Missing);
                    ws.Cells.Select();

                    Excel.Range sel = (Excel.Range)app.Selection;
                    sel.Copy(Type.Missing);

                    Excel._Worksheet sheet = (Excel._Worksheet)app.Workbooks[1].Worksheets.Add(
                        Type.Missing, Type.Missing, Type.Missing, Type.Missing
                        );

                    sheet.Paste(Type.Missing, Type.Missing);

                }


            }

        }
    }
}