Hi arujdevia,

Database

I have made use of the following table Customers with the schema as follows.

I have already inserted few records in the table.

You can download the database table SQL by clicking the download link below.

Download SQL file

HTML

<asp:Button Text="Export" OnClick="ExportExcel" runat="server" />

Namespaces

C#

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

VB.Net

Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient
Imports System.IO
Imports ClosedXML.Excel

Code

C#

protected void ExportExcel(object sender, EventArgs e)
{
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand("SELECT * FROM Customers"))
        {
            using (SqlDataAdapter sda = new SqlDataAdapter())
            {
                cmd.Connection = con;
                sda.SelectCommand = cmd;
                using (DataTable dt = new DataTable())
                {
                    sda.Fill(dt);
                    using (XLWorkbook wb = new XLWorkbook())
                    {
                        var ws = wb.Worksheets.Add(dt, "Customers");
                        ws.Table(0).ShowAutoFilter = false; // Disable AutoFilter.
                        ws.Table(0).Theme = XLTableTheme.None; // Remove Theme.
                        ws.Columns().AdjustToContents(); // Resize all columns.

                        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 ExportExcel(sender As Object, e As EventArgs)
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As New SqlConnection(constr)
        Using cmd As New SqlCommand("SELECT * FROM Customers")
            Using sda As New SqlDataAdapter()
                cmd.Connection = con
                sda.SelectCommand = cmd
                Using dt As New DataTable()
                    sda.Fill(dt)
                    Using wb As New XLWorkbook()
                        Dim ws = wb.Worksheets.Add(dt, "Customers")
                        ws.Table(0).ShowAutoFilter = False ' Disable AutoFilter.
                        ws.Table(0).Theme = XLTableTheme.None ' Remove Theme.
                        ws.Columns().AdjustToContents() ' Resize all columns.

                        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 New MemoryStream()
                            wb.SaveAs(MyMemoryStream)
                            MyMemoryStream.WriteTo(Response.OutputStream)
                            Response.Flush()
                            Response.End()
                        End Using
                    End Using
                End Using
            End Using
        End Using
    End Using
End Sub

Screenshot