epplus

Perfect! ✅ Let's replace Microsoft.Office.Interop.Excel with EPPlus, which:

• Doesn't require Microsoft Excel to be installed.
• Is much faster and more stable for server/desktop apps.

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🔧 Updated Requirements

• Read 2 Excel files.
• In File 1, "Icon Tracker" sheet → get Column M values.
• In File 2, "ICON management" sheet → get Column G values.
• If value in Column M is not in Column G, write "Icon not present in management Sheet" in Column N.
• Use EPPlus (works on .xlsx only).

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📦 Install EPPlus via NuGet

Run this in the NuGet Package Manager:

Install-Package EPPlus

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🧠 Updated ExcelService.cs using EPPlus

using OfficeOpenXml;
using System.Collections.Generic;
using System.IO;

namespace WpfIconCheckerApp.Models
{
    public class ExcelService
    {
        public static string CompareExcelFiles(string file1Path, string file2Path)
        {
            ExcelPackage.LicenseContext = LicenseContext.NonCommercial;

            try
            {
                // Load both Excel files
                using var package1 = new ExcelPackage(new FileInfo(file1Path));
                using var package2 = new ExcelPackage(new FileInfo(file2Path));

                var sheet1 = package1.Workbook.Worksheets["Icon Tracker"];
                var sheet2 = package2.Workbook.Worksheets["ICON management"];

                if (sheet1 == null || sheet2 == null)
                    return "One of the required sheets is missing.";

                // Read all values from Column G in sheet2 into a HashSet for fast lookup
                var iconsInManagementSheet = new HashSet<string>();
                int gRow = 2;
                while (!string.IsNullOrWhiteSpace(sheet2.Cells[gRow, 7].Text))
                {
                    iconsInManagementSheet.Add(sheet2.Cells[gRow, 7].Text.Trim());
                    gRow++;
                }

                // Loop through Column M in sheet1 and compare
                int mRow = 2;
                int unmatchedCount = 0;

                while (!string.IsNullOrWhiteSpace(sheet1.Cells[mRow, 13].Text))
                {
                    string icon = sheet1.Cells[mRow, 13].Text.Trim();

                    if (!iconsInManagementSheet.Contains(icon))
                    {
                        sheet1.Cells[mRow, 14].Value = "Icon not present in management Sheet"; // Column N
                        unmatchedCount++;
                    }

                    mRow++;
                }

                // Save updated file (overwrite or create new one)
                package1.Save();

                return $"Comparison done. {unmatchedCount} icons not found. Results written in Column N.";
            }
            catch (System.Exception ex)
            {
                return $"Error: {ex.Message}";
            }
        }
    }
}

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📝 Notes

• Column M = column 13
• Column G = column 7
• Column N = column 14
• EPPlus uses 1-based indexing
• File is saved in-place (same file is modified). Let me know if you want to save it to a new file.

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✅ No Change Needed in UI or ViewModel

Everything else in MainViewModel and MainWindow.xaml remains the same.

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Would you like me to:

• Save the result to a new Excel file?
• Show a file path to the updated file?
• Add logging or preview in a DataGrid?

Let me know how you'd like to extend it!