private void btnOk_Click(object sender, EventArgs e)
{
if (excelReader != null)
{
var inds = new HashSet <int>();
foreach (DataGridViewColumn col in dgvExcelInput.SelectedColumns)
{
inds.Add(col.Index);
}
ExcelData = ((DataTable)dgvExcelInput.DataSource).Copy();
for (int i = ExcelData.Columns.Count - 1; i >= 0; --i)
{
if (!inds.Contains(i))
{
ExcelData.Columns.RemoveAt(i);
}
}
ExcelData.ReplaceAllOccurrences(DBNull.Value, 0);
ExcelData.AcceptChanges();
}
}