Add header while exporting DataTable to Excel with ClosedXML using C# and VB.Net in ASP.Net

Hi thereallover0...,

Check this example. Now please take its reference and correct your code.

Namespaces

C#

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

VB.Net

Imports System.Data
Imports ClosedXML.Excel
Imports System.IO

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    DataTable dt = new DataTable();
    dt.Columns.AddRange(new DataColumn[] 
    {
        new DataColumn("Id", typeof(int)),
        new DataColumn("Name", typeof(string)),
        new DataColumn("Country", typeof(string))
    });
    dt.Rows.Add(1, "Mudassar Khan", "United States");
    dt.Rows.Add(2, "John Hammod", "India");
    dt.Rows.Add(3, "Robert Schidner", "France");
    dt.Rows.Add(4, "Suzanne Mathews", "Russia");

    using (XLWorkbook wb = new XLWorkbook())
    {
        var ws = wb.Worksheets.Add("worksheet");
        // Adding HeaderRow.
        ws.Cell("A1").Value = "Excelasoft Solutions";
        ws.Cell("A1").Style.Font.Bold = true;
        ws.Cell("A2").Value = "G-110, Shagun Arcade,Near Oberoi Mall,Malad (East),Mumbai 400097";

        if (dt.Rows.Count > 0)
        {

            ws.Cell("A4").Value = dt.Columns[0].ColumnName;
            ws.Cell("B4").Value = dt.Columns[1].ColumnName;
            ws.Cell("C4").Value = dt.Columns[2].ColumnName;

            // Adding DataRows.
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                ws.Cell("A" + (i + 5)).Value = dt.Rows[i][0];
                ws.Cell("B" + (i + 5)).Value = dt.Rows[i][1];
                ws.Cell("C" + (i + 5)).Value = dt.Rows[i][2];
            }
        }
        ws.Column(2).AdjustToContents();
        ws.Column(3).AdjustToContents();
        Response.Clear();
        Response.Buffer = true;
        Response.Charset = "";
        Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
        Response.AddHeader("content-disposition", "attachment;filename=Customer.xlsx");
        using (MemoryStream MyMemoryStream = new MemoryStream())
        {
            wb.SaveAs(MyMemoryStream);
            MyMemoryStream.WriteTo(Response.OutputStream);
            Response.Flush();
            Response.End();
        }
    }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    Dim dt As DataTable = New DataTable()
    dt.Columns.AddRange(New DataColumn() {
                        New DataColumn("Id", GetType(Integer)),
                        New DataColumn("Name", GetType(String)),
                        New DataColumn("Country", GetType(String))})
    dt.Rows.Add(1, "Mudassar Khan", "United States")
    dt.Rows.Add(2, "John Hammod", "India")
    dt.Rows.Add(3, "Robert Schidner", "France")
    dt.Rows.Add(4, "Suzanne Mathews", "Russia")

    Using wb As XLWorkbook = New XLWorkbook()
        Dim ws = wb.Worksheets.Add("worksheet")
        ws.Cell("A1").Value = "Excelasoft Solutions"
        ws.Cell("A1").Style.Font.Bold = True
        ws.Cell("A2").Value = "G-110, Shagun Arcade,Near Oberoi Mall,Malad (East),Mumbai 400097"

        If dt.Rows.Count > 0 Then
            ws.Cell("A4").Value = dt.Columns(0).ColumnName
            ws.Cell("B4").Value = dt.Columns(1).ColumnName
            ws.Cell("C4").Value = dt.Columns(2).ColumnName
            For i As Integer = 0 To dt.Rows.Count - 1
                ws.Cell("A" & (i + 5)).Value = dt.Rows(i)(0)
                ws.Cell("B" & (i + 5)).Value = dt.Rows(i)(1)
                ws.Cell("C" & (i + 5)).Value = dt.Rows(i)(2)
            Next
        End If

        ws.Column(2).AdjustToContents()
        ws.Column(3).AdjustToContents()
        Response.Clear()
        Response.Buffer = True
        Response.Charset = ""
        Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
        Response.AddHeader("content-disposition", "attachment;filename=Customer.xlsx")

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

Screenshot