Question

I’m importing data from an excel file and I just noticed that some cells are becoming ” ” after the import

Here’s the code I’m using

                FileUploadExcel.SaveAs("C:\\datatop.xls");
                string connectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\1.xls;Extended Properties=Excel 8.0;";


                using (OleDbConnection connection = new OleDbConnection(connectionString))
                {
                    connection.Open();
                    OleDbCommand command = new OleDbCommand("Select MONTH, QTY FROM [Sheet1$]", connection);
                    DataTable tb = new DataTable();
                    using (System.Data.Common.DbDataReader dr = command.ExecuteReader())
                    {
                        tb.Load(dr);
                    }
                    gv.DataSource = tb;
                    gv.DataBind();
                }

The column in question is QTY which contains:

12
14
15
11
19k/yr
4
2

It becomes a space on my gridview after the import. All other cells are displaying just fine on the gridview.

OUTPUT in GridView:

12
14
15
11

4
2

Any ideas?

Answer 1

When using OLEDB with Excel, the data type of a column is determined by the first few items in each column. In your case, the first few items in the column are numbers, so it assumes the column is of type int. If you want the column to be considered text, you need to make sure you have some dummy rows at the top with data that ensures the right data types, then filter out those rows once the data is read into the data table. I know it’s a cluge, but it should work.

Edit – Alternative: Using Excel Interop/COM to fill a DataTable

using Microsoft.Office.Interop.Excel;
using Sd = System.Data;

private void FillTableData(Sd.DataTable table, Worksheet worksheet, Range cells)
{
    using (var com = new ComObjectManager())
    {
        var firstCell = GetFirstCell(com, cells);
        var beginCell = com.Get<Range>(() => (Range)cells.Item[2, 1]);
        var endCell = GetLastContiguousCell(com, cells, firstCell);
        if (beginCell.Value == null) return;
        var range = GetRange(com, cells, beginCell, endCell);
        var data = (object[,])range.Value;
        var rowCount = data.GetLength(0);
        for (var rowIndex = 0; rowIndex < rowCount; rowIndex++)
        {
            var values = new object[table.Columns.Count];
            for (var columnIndex = 0; columnIndex < table.Columns.Count; columnIndex++)
            {
                var value = data[rowIndex + 1, columnIndex + 1];
                values[columnIndex] = value;
            }
            table.Rows.Add(values);
        }
    }
}

private Range GetFirstCell(ComObjectManager com, Range cells)
{
    return com.Get<Range>(() => (Range)cells.Item[1, 1]);
}

private Range GetLastContiguousCell(ComObjectManager com, Range cells, Range beginCell)
{
    var bottomCell = com.Get<Range>(() => beginCell.End[XlDirection.xlDown]);
    var rightCell = com.Get<Range>(() => beginCell.End[XlDirection.xlToRight]);
    return com.Get<Range>(() => (Range)cells.Item[bottomCell.Row, rightCell.Column]);
}

ComObjectManager – ensures that COM objects are properly disposed after being used

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;

public class ComObjectManager : IDisposable
{
    private Stack<object> _comObjects = new Stack<object>();

    public TComObject Get<TComObject>(Func<TComObject> getter)
    {
        var comObject = getter();
        _comObjects.Push(comObject);
        return comObject;
    }

    public void Dispose()
    {
        while (_comObjects.Count > 0)
            Marshal.ReleaseComObject(_comObjects.Pop());
    }
}