使用asp.net使字母表值为空的Excel列数据

using System;
using System.Text.RegularExpressions;
using Microsoft.Office.Interop.Excel;

protected void Button1_Click(object sender, EventArgs e)
{
    // 打开Excel文件
    Application excelApp = new Application();
    Workbook workbook = excelApp.Workbooks.Open("路径/文件名.xlsx");
    Worksheet worksheet = workbook.Worksheets[1];

    // 获取数据范围
    Range range = worksheet.UsedRange;

    // 遍历每个单元格
    foreach (Range cell in range.Cells)
    {
        // 获取单元格的值
        string value = cell.Value.ToString();

        // 判断是否为字母
        if (Regex.IsMatch(value, @"^[a-zA-Z]+$"))
        {
            // 将字母单元格的值设置为空字符串
            cell.Value = "";
        }
    }

    // 保存并关闭Excel文件
    workbook.Save();
    workbook.Close();
    excelApp.Quit();
}