<dx:BootstrapSpreadsheet ID="SpreadsheetCustomDataMerging" runat="server" ActiveTabIndex="0" ShowConfirmOnLosingChanges="false"
    OnLoad="SpreadsheetCustomDataMerging_Load">
</dx:BootstrapSpreadsheet>

int StartRowIndex = 10,
    MaxReportRowsCount = 15;
protected Worksheet Worksheet { get { return SpreadsheetCustomDataMerging.Document.Worksheets.ActiveWorksheet; } }
protected void SpreadsheetCustomDataMerging_Load(object sender, EventArgs e) {
    if(!Page.IsPostBack) {
        SpreadsheetCustomDataMerging.Open(Path.Combine(DirectoryManagmentUtils.CurrentDataDirectory, @"Spreadsheet\\ExpenseReport.xlsx"));
        var expenses = LoadExpensesReportData();
        FillGeneralReportInfo(expenses.Info);
        FillReport(expenses.Expenses);
        SpreadsheetCustomDataMerging.Document.Worksheets.ActiveWorksheet.ActiveView.ShowGridlines = false;
        SpreadsheetCustomDataMerging.Document.History.Clear();
    }
}
ExpensesReport LoadExpensesReportData() {
    using(Stream stream = File.OpenRead(HttpContext.Current.Server.MapPath("~/App_Data/Expenses.xml"))) {
        var serializer = new System.Xml.Serialization.XmlSerializer(typeof(ExpensesReport));
        return (ExpensesReport)serializer.Deserialize(stream);
    }
}
void FillGeneralReportInfo(ExpensesInfo info) {
    Worksheet["D2"].Value = info.Purpose;
    Worksheet["D3"].Value = info.StatementNumber;
    Worksheet["C7"].Value = info.EmployeeName;
    Worksheet["C8"].Value = info.EmployeeDepartment;
    Worksheet["G7"].Value = info.EmployeePosition;
    Worksheet["G8"].Value = info.Manager;
    Worksheet["K7"].Value = info.SSN;
    Worksheet["K8"].Value = info.EmployeeID;
}
void FillReport(List<Expense> report) {
    int reportCount = Math.Min(report.Count, MaxReportRowsCount);
    for(int i = 0; i < reportCount; i++) {
        Expense expense = report[i];
        int rowOffset = StartRowIndex + i + 1;
        Worksheet["B" + rowOffset].Value = expense.CreationDate;
        Worksheet["C" + rowOffset].Value = expense.Account;
        Worksheet["D" + rowOffset].Value = expense.Description;
        Worksheet["F" + rowOffset].Value = expense.Hotel;
        Worksheet["H" + rowOffset].Value = expense.Transport;
        Worksheet["I" + rowOffset].Value = expense.Fuel;
        Worksheet["J" + rowOffset].Value = expense.Meals;
        Worksheet["L" + rowOffset].Value = expense.Phone;
        Worksheet["M" + rowOffset].Value = expense.Entertainment;
        Worksheet["N" + rowOffset].Value = expense.Misc;
    }
}
[XmlRoot("Expenses")]
public class ExpensesReport {
    public ExpensesReport() {
        Info = new ExpensesInfo();
        Expenses = new List<Expense>();
    }
    [XmlElement]
    public ExpensesInfo Info { get; set; }
    [XmlElement("Expense")]
    public List<Expense> Expenses { get; set; }
}
public class ExpensesInfo {
    [XmlAttribute]
    public string Purpose { get; set; }
    [XmlAttribute]
    public int StatementNumber { get; set; }
    [XmlAttribute]
    public int EmployeeID { get; set; }
    [XmlAttribute]
    public string EmployeeName { get; set; }
    [XmlAttribute]
    public string EmployeePosition { get; set; }
    [XmlAttribute]
    public string SSN { get; set; }
    [XmlAttribute]
    public string EmployeeDepartment { get; set; }
    [XmlAttribute]
    public string Manager { get; set; }
}
public class Expense {
    [XmlAttribute(AttributeName = "Date")]
    public DateTime CreationDate { get; set; }
    [XmlAttribute]
    public int Account { get; set; }
    [XmlAttribute]
    public string Description { get; set; }
    [XmlAttribute]
    public double Hotel { get; set; }
    [XmlAttribute]
    public double Transport { get; set; }
    [XmlAttribute]
    public double Fuel { get; set; }
    [XmlAttribute]
    public double Meals { get; set; }
    [XmlAttribute]
    public double Phone { get; set; }
    [XmlAttribute]
    public double Misc { get; set; }
    [XmlAttribute]
    public double Entertainment { get; set; }
}