Iterating and adding all column names to a ComboBox using EPPlus

Question

I need to add the column names within a sheet to a combobox

I have tried the following

 var pck = new OfficeOpenXml.ExcelPackage();
            pck.Load(new System.IO.FileInfo("test.xlsx").OpenRead());
            var ws = pck.Workbook.Worksheets[1];

            int totalCols = ws.Dimension.End.Column;

            for (int i = 1; i <= totalCols; i++)
            {
              comboBox1.Items.Add(  (ws.Column(i).ToString()));
            }
        }

But this produces a Null Reference Exception.

Why is that happening?

Answer 1

Ensure that you're loading the package correctly and selecting the values correctly:

// Select workbook
var fileInfo = new FileInfo(@"yourfile.xlsx");

// Load workbook
using (var package = new ExcelPackage(fileInfo)) {
// Itterate through workbook sheets
    foreach (var sheet in package.Workbook.Worksheets){
// Itterate through each column until final column
        for (int i = 1; i <= sheet.Dimension.End.Column; i++) {
            comboBox1.Items.Add(sheet.Cells[1, i].Text);
        }
    }
}

This runs correctly in a new workbook with two sheets and values in the columns of each sheet.