在 C# 中下载文件并将权限设置为“所有人”，但我看到访问被拒绝

我使用ExcelLibrary，保存Excel文件后，我想通过WebClient下载它，我为文件夹设置了完全控制，但我看到访问被拒绝。

我的代码是：

public class GenerateExcelClass
{
    System.Data.DataTable dtCustmer = new System.Data.DataTable();
    object[] query;
    public void CreateExcelClass<T>(T[] listObj, string fileName, string sheetName = "sheet")
    {
        string generatefileName = fileName + HttpContext.Current.Request.Cookies["ImenBourse"]["userId"];
        dtCustmer = ConvertToDatatable(listObj);
        DataSet ds = new DataSet("New_DataSet");
        ds.Locale = System.Threading.Thread.CurrentThread.CurrentCulture;
        ds.Tables.Add(dtCustmer);
        string newFilePath = HttpContext.Current.Server.MapPath(generatefileName + ".xls");
        ExcelLibrary.DataSetHelper.CreateWorkbook(newFilePath, ds);
        WebClient webClient = new WebClient();
        var path = HttpContext.Current.Server.MapPath("");
        webClient.DownloadFile(path, generatefileName + ".xls");
    }
    public static DataTable ConvertToDatatable<T>(T[] list)
    {
        PropertyInfo[] properties = list.GetType().GetElementType().GetProperties();
        DataTable dt = CreateDataTable(properties);
        if (list.Length != 0)
        {
            foreach (object o in list)
                FillData(properties, dt, o);
        }
        return dt;
    }
    private static DataTable CreateDataTable(PropertyInfo[] properties)
    {
        DataTable dt = new DataTable();
        DataColumn dc = null;
        foreach (PropertyInfo pi in properties)
        {
            DisplayNameAttribute attr = (DisplayNameAttribute)Attribute.GetCustomAttribute(pi, typeof(DisplayNameAttribute));
            dt.Columns.Add(attr.DisplayName, pi.PropertyType);
        }
        return dt;
    }
    private static void FillData(PropertyInfo[] properties, DataTable dt, Object o)
    {
        DataRow dr = dt.NewRow();
        foreach (PropertyInfo pi in properties)
        {
            DisplayNameAttribute attr = (DisplayNameAttribute)Attribute.GetCustomAttribute(pi, typeof(DisplayNameAttribute));
            if (dt.Columns.Contains(attr.DisplayName))
            {
                dr[attr.DisplayName] = pi.GetValue(o, null);
            }
        }
        dt.Rows.Add(dr);
    }
}