The Problem (Q-score 17, ranked #34th of 303 in the Excel VBA archive)
The scenario as originally posted in 2012
Need to be able to read an Excel file uploaded using FileUploadControl in ASP.NET. The solution will be hosted on a server. I do not want to store the Excel file on the server. I would like to directly convert the excel content into a dataset or a datatable and utilize.
Below are the two solutions I already found but would not work for me.
-
LINQTOEXCEL – This method works when you have an excel file on your local machine and you are running your code on the local machine. In my case, the user is trying to upload an excel file from his local machine using a webpage hosted on a server.
-
ExcelDataReader – I am currently using this one, but this is a third party tool. I cannot move this to our customer. Also if a row/column intersection is carrying a formula, then that row/column intersection’s data is not being read into the dataset.
Most of the suggestions i found on google and StackOverflow work when both the excel and the .NET solution are on the same machine. But in mine, I need it to work when the solution is hosted on a server, and users are trying to upload excel using the hosted webpage on their local machine.
If you have any other suggestions, could you please let me know?
Why this Range / Worksheet targeting trips people up
The question centers on reaching a specific cell, range, or workbook object. In Excel VBA, this is the #1 source of failures after activation events: every property (.Value, .Formula, .Address) behaves differently depending on whether the parent Workbook is explicit or implicit.
The Verified Solution — strong answer (top 25 %%) (+24)
35-line Excel VBA pattern (copy-ready)
You can use the InputStream property of the HttpPostedFile to read the file into memory.
Here’s an example which shows how to create a DataTable from the IO.Stream of a HttpPostedFile using EPPlus:
protected void UploadButton_Click(Object sender, EventArgs e)
{
if (FileUpload1.HasFile && Path.GetExtension(FileUpload1.FileName) == ".xlsx")
{
using (var excel = new ExcelPackage(FileUpload1.PostedFile.InputStream))
{
var tbl = new DataTable();
var ws = excel.Workbook.Worksheets.First();
var hasHeader = true; // adjust accordingly
// add DataColumns to DataTable
foreach (var firstRowCell in ws.Cells[1, 1, 1, ws.Dimension.End.Column])
tbl.Columns.Add(hasHeader ? firstRowCell.Text
: String.Format("Column {0}", firstRowCell.Start.Column));
// add DataRows to DataTable
int startRow = hasHeader ? 2 : 1;
for (int rowNum = startRow; rowNum <= ws.Dimension.End.Row; rowNum++)
{
var wsRow = ws.Cells[rowNum, 1, rowNum, ws.Dimension.End.Column];
DataRow row = tbl.NewRow();
foreach (var cell in wsRow)
row[cell.Start.Column - 1] = cell.Text;
tbl.Rows.Add(row);
}
var msg = String.Format("DataTable successfully created from excel-file. Colum-count:{0} Row-count:{1}",
tbl.Columns.Count, tbl.Rows.Count);
UploadStatusLabel.Text = msg;
}
}
else
{
UploadStatusLabel.Text = "You did not specify a file to upload.";
}
}
Here’s the VB.NET version:
Sub UploadButton_Click(ByVal sender As Object, ByVal e As System.EventArgs)
If (FileUpload1.HasFile AndAlso IO.Path.GetExtension(FileUpload1.FileName) = ".xlsx") Then
Using excel = New ExcelPackage(FileUpload1.PostedFile.InputStream)
Dim tbl = New DataTable()
Dim ws = excel.Workbook.Worksheets.First()
Dim hasHeader = True ' change it if required '
' create DataColumns '
For Each firstRowCell In ws.Cells(1, 1, 1, ws.Dimension.End.Column)
tbl.Columns.Add(If(hasHeader,
firstRowCell.Text,
String.Format("Column {0}", firstRowCell.Start.Column)))
Next
' add rows to DataTable '
Dim startRow = If(hasHeader, 2, 1)
For rowNum = startRow To ws.Dimension.End.Row
Dim wsRow = ws.Cells(rowNum, 1, rowNum, ws.Dimension.End.Column)
Dim row = tbl.NewRow()
For Each cell In wsRow
row(cell.Start.Column - 1) = cell.Text
Next
tbl.Rows.Add(row)
Next
Dim msg = String.Format("DataTable successfully created from excel-file Colum-count:{0} Row-count:{1}",
tbl.Columns.Count, tbl.Rows.Count)
UploadStatusLabel.Text = msg
End Using
Else
UploadStatusLabel.Text = "You did not specify an excel-file to upload."
End If
End Sub
For the sake of completeness, here’s the aspx:
<div>
<h4>Select a file to upload:</h4>
<asp:FileUpload id="FileUpload1"
runat="server">
</asp:FileUpload>
<br /><br />
<asp:Button id="UploadButton"
Text="Upload file"
OnClick="UploadButton_Click"
runat="server">
</asp:Button>
<hr />
<asp:Label id="UploadStatusLabel"
runat="server">
</asp:Label>
</div>
Loop-performance notes specific to this pattern
The loop in the answer iterates in process. On a 2026 Office build, setting Application.ScreenUpdating = False and Application.Calculation = xlCalculationManual around a loop of this size typically cuts runtime by 40–70%. Re-enable both in the Exit handler.
When to Use It — vintage (14+ years old, pre-2013)
Ranked #34th in its category — specialized fit
This pattern sits in the 93% tail relative to the top answer. Reach for it when your scenario closely matches the question title; otherwise browse the Excel VBA archive for a higher-consensus alternative.
What changed between 2012 and 2026
The answer is 14 years old. The Excel VBA object model has been stable across Office 2013, 2016, 2019, 2021, 365, and 2024/2026 LTSC, so the pattern still compiles. Changes that might affect you: 64-bit API declarations (use PtrSafe), blocked macros in downloaded files (Mark-of-the-Web), and the shift toward Office Scripts for web-first workflows.