using IronXL;
using IronXL.Styles;
using System;
using System.Data;
using System.IO;
using System.Windows.Forms;

private void btnExport_Click(object sender, EventArgs e)
{
    DataTable dt = (DataTable)GridView1.DataSource;
    WorkBook workBook = WorkBook.Create(ExcelFileFormat.XLSX);
    WorkSheet workSheet = workBook.DefaultWorkSheet;
    // Export header row with formatting
    for (int col = 0; col < dt.Columns.Count; col++)
    {
        workSheet.SetCellValue(0, col, dt.Columns[col].ColumnName);
        var cell = workSheet.GetCellAt(0, col);
        cell.Style.Font.Bold = true;
        cell.Style.SetBackgroundColor("#4472C4");
        cell.Style.Font.Color = "#FFFFFF";
        cell.Style.BottomBorder.Type = BorderType.Thin;
    }
    // Export data rows with alternating row color
    for (int row = 0; row < dt.Rows.Count; row++)
    {
        for (int col = 0; col < dt.Columns.Count; col++)
        {
            var cellValue = dt.Rows[row][col];
            workSheet.SetCellValue(row + 1, col, cellValue?.ToString() ?? "");
            var cell = workSheet.GetCellAt(row + 1, col);
            string bgColor = (row % 2 == 0) ? "#D6DCE5" : "#FFFFFF";
            cell.Style.SetBackgroundColor(bgColor);
            cell.Style.BottomBorder.Type = BorderType.Thin;
        }
    }
    // Save and write response for download
    MemoryStream stream = workBook.ToStream();
    using (SaveFileDialog saveFileDialog = new SaveFileDialog())
    {
        saveFileDialog.Filter = "Excel Files|*.xlsx";
        saveFileDialog.Title = "Save Excel File";
        saveFileDialog.FileName = "GridViewExport.xlsx";
        if (saveFileDialog.ShowDialog() == DialogResult.OK)
        {
            using (FileStream fileStream = new FileStream(saveFileDialog.FileName, FileMode.Create, FileAccess.Write))
            {
                stream.WriteTo(fileStream);
            }
            MessageBox.Show("Export successful.", "Export", MessageBoxButtons.OK, MessageBoxIcon.Information);
        }
    }
}

Imports IronXL
Imports IronXL.Styles
Imports System
Imports System.Data
Imports System.IO
Imports System.Windows.Forms

Private Sub btnExport_Click(sender As Object, e As EventArgs) Handles btnExport.Click
    Dim dt As DataTable = DirectCast(GridView1.DataSource, DataTable)
    Dim workBook As WorkBook = WorkBook.Create(ExcelFileFormat.XLSX)
    Dim workSheet As WorkSheet = workBook.DefaultWorkSheet
    ' Export header row with formatting
    For col As Integer = 0 To dt.Columns.Count - 1
        workSheet.SetCellValue(0, col, dt.Columns(col).ColumnName)
        Dim cell = workSheet.GetCellAt(0, col)
        cell.Style.Font.Bold = True
        cell.Style.SetBackgroundColor("#4472C4")
        cell.Style.Font.Color = "#FFFFFF"
        cell.Style.BottomBorder.Type = BorderType.Thin
    Next
    ' Export data rows with alternating row color
    For row As Integer = 0 To dt.Rows.Count - 1
        For col As Integer = 0 To dt.Columns.Count - 1
            Dim cellValue = dt.Rows(row)(col)
            workSheet.SetCellValue(row + 1, col, If(cellValue?.ToString(), ""))
            Dim cell = workSheet.GetCellAt(row + 1, col)
            Dim bgColor As String = If(row Mod 2 = 0, "#D6DCE5", "#FFFFFF")
            cell.Style.SetBackgroundColor(bgColor)
            cell.Style.BottomBorder.Type = BorderType.Thin
        Next
    Next
    ' Save and write response for download
    Dim stream As MemoryStream = workBook.ToStream()
    Using saveFileDialog As New SaveFileDialog()
        saveFileDialog.Filter = "Excel Files|*.xlsx"
        saveFileDialog.Title = "Save Excel File"
        saveFileDialog.FileName = "GridViewExport.xlsx"
        If saveFileDialog.ShowDialog() = DialogResult.OK Then
            Using fileStream As New FileStream(saveFileDialog.FileName, FileMode.Create, FileAccess.Write)
                stream.WriteTo(fileStream)
            End Using
            MessageBox.Show("Export successful.", "Export", MessageBoxButtons.OK, MessageBoxIcon.Information)
        End If
    End Using
End Sub