Hi shalinip,

Please refer below sample.

You can download the dll from the below article.

Read Excel file directly from Stream in ASP.Net

HTML

<div>
    <asp:FileUpload ID="FileUpload1" runat="server" />
    <asp:Button ID="btnImport" runat="server" Text="CopyToExcel" OnClick="ImportExcel" />
</div>

Namespaces

C#

using System.IO;
using System.Data;
using ClosedXML.Excel;

VB.Net

Imports System.IO
Imports System.Data
Imports System.Collections.Generic
Imports ClosedXML.Excel

Code

C#

protected void ImportExcel(object sender, EventArgs e)
{
    using (XLWorkbook workBook = new XLWorkbook(FileUpload1.PostedFile.InputStream))
    {
        IXLWorksheet workSheet = workBook.Worksheet(1);
        DataTable dt = new DataTable();
        bool firstRow = true;
        foreach (IXLRow row in workSheet.Rows())
        {
            if (firstRow)
            {
                foreach (IXLCell cell in row.Cells())
                {
                    dt.Columns.Add(cell.Value.ToString());
                }
                firstRow = false;
            }
            else
            {
                dt.Rows.Add();
                int i = 0;
                foreach (IXLCell cell in row.Cells())
                {
                    dt.Rows[dt.Rows.Count - 1][i] = cell.Value.ToString();
                    i++;
                }
            }
        }
        using (XLWorkbook wb = new XLWorkbook())
        {
            wb.Worksheets.Add(dt, "Customers");

            Response.Clear();
            Response.Buffer = true;
            Response.Charset = "";
            Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
            Response.AddHeader("content-disposition", "attachment;filename=SqlExport.xlsx");
            using (MemoryStream MyMemoryStream = new MemoryStream())
            {
                wb.SaveAs(MyMemoryStream);
                MyMemoryStream.WriteTo(Response.OutputStream);
                Response.Flush();
                Response.End();
            }
        }
    }
}

VB.Net

Protected Sub ImportExcel(ByVal sender As Object, ByVal e As EventArgs)
    Using workBook As XLWorkbook = New XLWorkbook(FileUpload1.PostedFile.InputStream)
        Dim workSheet As IXLWorksheet = workBook.Worksheet(1)
        Dim dt As DataTable = New DataTable()
        Dim firstRow As Boolean = True
        For Each row As IXLRow In workSheet.Rows()
            If firstRow Then

                For Each cell As IXLCell In row.Cells()
                    dt.Columns.Add(cell.Value.ToString())
                Next
                firstRow = False
            Else
                dt.Rows.Add()
                Dim i As Integer = 0

                For Each cell As IXLCell In row.Cells()
                    dt.Rows(dt.Rows.Count - 1)(i) = cell.Value.ToString()
                    i += 1
                Next
            End If
        Next
        Using wb As XLWorkbook = New XLWorkbook()
            wb.Worksheets.Add(dt, "Customers")
            Response.Clear()
            Response.Buffer = True
            Response.Charset = ""
            Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
            Response.AddHeader("content-disposition", "attachment;filename=SqlExport.xlsx")
            Using MyMemoryStream As MemoryStream = New MemoryStream()
                wb.SaveAs(MyMemoryStream)
                MyMemoryStream.WriteTo(Response.OutputStream)
                Response.Flush()
                Response.End()
            End Using
        End Using
    End Using
End Sub

Screenshot