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change cell color in ClosedXML while exporting sql data to excel

I need to change the color of a particular cell based on some conditions. I am already exporting whole table from MySQL to Excel, after exporting to Excel I want to change cell color in Excel file.
I am using ClosedXML library in C#.NET for exporting to Excel.
private void ExportDataSetToExcel(DataSet ds)
{
string[] paths = { Path.GetFullPath(#"..\..\"), "ExcelFiles" };
string fullPath = Path.Combine(paths);
string file = fullPath + "\\DataFile.xlsx";
using (XLWorkbook wb = new XLWorkbook())
{
wb.Worksheets.Add(ds.Tables[0]);
wb.Style.Alignment.Horizontal = XLAlignmentHorizontalValues.Center;
wb.Style.Font.Bold = true;
wb.Style.Fill.BackgroundColor.SetColor(Color.LightGreen);
wb.SaveAs(file);
}
}

Try this,
ws.Row(6).Style.Fill.BackgroundColor = XLColor.Blue
ws.Column("E").Style.Fill.BackgroundColor = XLColor.Blue;

Reading large Excel files with c# and get the indexes

I tried to use Microsoft.Office.Interop.Excel but it's too slow when it comes to reading large excel documents (it was taking over 5 minutes for me). I read that DocumentFormat.OpenXml is faster when it comes to reading large excel documents but in the documentation it doesn't appear that I can't store the columns and row indexes.
For now, I am also only interested in the first row to get the column headers and I will be reading the rest of the document after some logic. I haven't been able to find a way to read only a portion of the excel document. I want to do something similar to this:
int r = 1; //row index
int c = 1; //column index
while (xlRange.Cells[r,c] != null && xlRange.Cells[r, c].Value2 != null)
{
TagListData.Add(new TagClass { IsTagSelected = false, TagName = xlRange[r, c].Value2.toString(), rIndex = r, cIndex = c });
c += 3;
}
Users will be picking excel documents through openFileDialog so there's no fixed number of rows of columns I can use. Is there a way I could make this work?
Thank you

In OpenXML if a cell has no text it might or might not appear in the list of cells (depends on whether it ever had text or not). Therefore the while (...Value2 != null) type of approach isn't really a safe way to do things in OpenXML.
Here is a very simple approach to reading the first row (written using LINQPad hence the Main and the Dump). Note the (simplified) use of the SharedStringTable to get the real text of the cell:
void Main()
{
var fileName = #"c:\temp\openxml-read-row.xlsx";
using (FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
{
using (SpreadsheetDocument doc = SpreadsheetDocument.Open(fs, false))
{
// Get the necessary bits of the doc
WorkbookPart workbookPart = doc.WorkbookPart;
SharedStringTablePart sstpart = workbookPart.GetPartsOfType<SharedStringTablePart>().First();
SharedStringTable sst = sstpart.SharedStringTable;
WorkbookStylesPart ssp = workbookPart.GetPartsOfType<WorkbookStylesPart>().First();
Stylesheet ss = ssp.Stylesheet;
// Get the first worksheet
WorksheetPart worksheetPart = workbookPart.WorksheetParts.First();
Worksheet sheet = worksheetPart.Worksheet;
var rows = sheet.Descendants<Row>();
var row = rows.First();
foreach (var cell in row.Descendants<Cell>())
{
var txt = GetCellText(cell, sst);
// LINQPad specific method .Dump()
$"{cell.CellReference} = {txt}".Dump();
}
}
}
}
// Very basic way to get the text of a cell
private string GetCellText(Cell cell, SharedStringTable sst)
{
if (cell == null)
return "";
if ((cell.DataType != null) && (cell.DataType == CellValues.SharedString))
{
int ssid = int.Parse(cell.CellValue.Text);
string str = sst.ChildElements[ssid].InnerText;
return str;
}
else if (cell.CellValue != null)
{
return cell.CellValue.Text;
}
return "";
}
However... there's potentially a lot of work involved with OpenXML and you'd be well advised to try and use something like ClosedXML or EPPlus instead.
eg using ClosedXML
using (var workbook = new XLWorkbook(fileName))
{
var worksheet = workbook.Worksheets.First();
var row = worksheet.Row(1);
foreach (var cell in row.CellsUsed())
{
var txt = cell.Value.ToString();
// LINQPad specific method .Dump()
$"{cell.Address.ToString()} = {txt}".Dump();
}
}

transfer from c# to excel with multiple sheets

I have a few different dictionaries with different categories of information and I need to output them all into an xls or csv file with multiple spreadsheets. Currently, I have to download each excel file for a specific date range individually and then copy and paste them together so they're on different sheets of the same file. Is there any way to download all of them together in one document? Currently, I use the following code to output their files:
writeCsvToStream(
organize.ToDictionary(k => k.Key, v => v.Value as IacTransmittal), writer
);
ms.Seek(0, SeekOrigin.Begin);
Response.Clear();
Response.AddHeader("Content-Disposition", "attachment; filename=" + fileName);
Response.AddHeader("Content-Length", ms.Length.ToString());
Response.ContentType = "application/octet-stream";
ms.CopyTo(Response.OutputStream);
Response.End();
where writeCsvToStream just creates the text for the individual file.

There are some different options you could use.
ADO.NET Excel driver - with this API you can populate data into Excel documents using SQL style syntax. Each worksheet in the workbook is a table, each column header in a worksheet is a column in that table etc.
Here is a code project article on the exporting to Excel using ADO.NET:
http://www.codeproject.com/Articles/567155/Work-with-MS-Excel-and-ADO-NET
The ADO.NET approach is safe to use in a multi-user, web app environment.
Use OpenXML to export the data
OpenXML is a schema definition for different types of documents and the later versions of Excel (the ones that use .xlsx, .xlsm etc. instead of just .xls) use this format for the documents. The OpenXML schema is huge and somewhat cumbersome, however you can do pretty much anything with it.
Here is a code project article on exporting data to Excel using OpenXML:
http://www.codeproject.com/Articles/692121/Csharp-Export-data-to-Excel-using-OpenXML-librarie
The OpenXML approach is safe to use in a multi-user, web app environment.
A third approach is to use COM automation which is the same as programmatically running an instance of the Excel desktop application and using COM to control the actions of that instance.
Here is an article on that topic:
http://support.microsoft.com/kb/302084
Note that this third approach (office automation) is not safe in a multi-user, web app environment. I.e. it should not be used on a server, only from standalone desktop applications.

If you're open to learning a new library, I highly recommend EPPlus.
I'm making a few assumptions here since you didn't post much code to translate, but an example of usage may look like this:
using OfficeOpenXml;
using OfficeOpenXml.Style;
public static void WriteXlsOutput(Dictionary<string, IacTransmittal> collection) //accepting one dictionary as a parameter
{
using (FileStream outFile = new FileStream("Example.xlsx", FileMode.Create))
{
using (ExcelPackage ePackage = new ExcelPackage(outFile))
{
//group the collection by date property on your class
foreach (IGrouping<DateTime, IacTransmittal> collectionByDate in collection
.OrderBy(i => i.Value.Date.Date)
.GroupBy(i => i.Value.Date.Date)) //assuming the property is named Date, using Date property of DateTIme so we only create new worksheets for individual days
{
ExcelWorksheet eWorksheet = ePackage.Workbook.Worksheets.Add(collectionByDate.Key.Date.ToString("yyyyMMdd")); //add a new worksheet for each unique day
Type iacType = typeof(IacTransmittal);
PropertyInfo[] iacProperties = iacType.GetProperties();
int colCount = iacProperties.Count(); //number of properties determines how many columns we need
//set column headers based on properties on your class
for (int col = 1; col <= colCount; col++)
{
eWorksheet.Cells[1, col].Value = iacProperties[col - 1].Name ; //assign the value of the cell to the name of the property
}
int rowCounter = 2;
foreach (IacTransmittal iacInfo in collectionByDate) //iterate over each instance of this class in this igrouping
{
int interiorColCount = 1;
foreach (PropertyInfo iacProp in iacProperties) //iterate over properties on the class
{
eWorksheet.Cells[rowCounter, interiorColCount].Value = iacProp.GetValue(iacInfo, null); //assign cell values by getting the value of each property in the class
interiorColCount++;
}
rowCounter++;
}
}
ePackage.Save();
}
}
}

Thanks for the ideas! I was eventually able to figure out the following
using Excel = Microsoft.Office.Interop.Excel;
Excel.Application ExcelApp = new Excel.Application();
Excel.Workbook ExcelWorkBook = null;
Excel.Worksheet ExcelWorkSheet = null;
ExcelApp.Visible = true;
ExcelWorkBook = ExcelApp.Workbooks.Add(Excel.XlWBATemplate.xlWBATWorksheet);
List<string> SheetNames = new List<string>()
{ "Sheet1", "Sheet2", "Sheet3", "Sheet4", "Sheet5", "Sheet6", "Sheet7"};
string [] headers = new string []
{ "Field 1", "Field 2", "Field 3", "Field 4", "Field 5" };
for (int i = 0; i < SheetNames.Count; i++)
ExcelWorkBook.Worksheets.Add(); //Adding New sheet in Excel Workbook
for (int k = 0; k < SheetNames.Count; k++ )
{
int r = 1; // Initialize Excel Row Start Position = 1
ExcelWorkSheet = ExcelWorkBook.Worksheets[k + 1];
//Writing Columns Name in Excel Sheet
for (int col = 1; col < headers.Length + 1; col++)
ExcelWorkSheet.Cells[r, col] = headers[col - 1];
r++;
switch (k)
{
case 0:
foreach (var kvp in Sheet1)
{
ExcelWorkSheet.Cells[r, 1] = kvp.Value.Field1;
ExcelWorkSheet.Cells[r, 2] = kvp.Value.Field2;
ExcelWorkSheet.Cells[r, 3] = kvp.Value.Field3;
ExcelWorkSheet.Cells[r, 4] = kvp.Value.Field4;
ExcelWorkSheet.Cells[r, 5] = kvp.Value.Field5;
r++;
}
break;
}
ExcelWorkSheet.Name = SheetNames[k];//Renaming the ExcelSheets
}
//Activate the first worksheet by default.
((Excel.Worksheet)ExcelApp.ActiveWorkbook.Sheets[1]).Activate();
//Save As the excel file.
ExcelApp.ActiveWorkbook.SaveCopyAs(#"out_My_Book1.xls");

Optimal way to Read an Excel file (.xls/.xlsx)

I know that there are different ways to read an Excel file:
Iterop
Oledb
Open Xml SDK
Compatibility is not a question because the program will be executed in a controlled environment.
My Requirement :
Read a file to a DataTable / CUstom Entities (I don't know how to make dynamic properties/fields to an object[column names will be variating in an Excel file])
Use DataTable/Custom Entities to perform some operations using its data.
Update DataTable with the results of the operations
Write it back to excel file.
Which would be simpler.
Also if possible advice me on custom Entities (adding properties/fields to an object dynamically)

Take a look at Linq-to-Excel. It's pretty neat.
var book = new LinqToExcel.ExcelQueryFactory(#"File.xlsx");
var query =
from row in book.Worksheet("Stock Entry")
let item = new
{
Code = row["Code"].Cast<string>(),
Supplier = row["Supplier"].Cast<string>(),
Ref = row["Ref"].Cast<string>(),
}
where item.Supplier == "Walmart"
select item;
It also allows for strongly-typed row access too.

I realize this question was asked nearly 7 years ago but it's still a top Google search result for certain keywords regarding importing excel data with C#, so I wanted to provide an alternative based on some recent tech developments.
Importing Excel data has become such a common task to my everyday duties, that I've streamlined the process and documented the method on my blog: best way to read excel file in c#.
I use NPOI because it can read/write Excel files without Microsoft Office installed and it doesn't use COM+ or any interops. That means it can work in the cloud!
But the real magic comes from pairing up with NPOI Mapper from Donny Tian because it allows me to map the Excel columns to properties in my C# classes without writing any code. It's beautiful.
Here is the basic idea:
I create a .net class that matches/maps the Excel columns I'm interested in:
class CustomExcelFormat
{
[Column("District")]
public int District { get; set; }
[Column("DM")]
public string FullName { get; set; }
[Column("Email Address")]
public string EmailAddress { get; set; }
[Column("Username")]
public string Username { get; set; }
public string FirstName
{
get
{
return Username.Split('.')[0];
}
}
public string LastName
{
get
{
return Username.Split('.')[1];
}
}
}
Notice, it allows me to map based on column name if I want to!
Then when I process the excel file all I need to do is something like this:
public void Execute(string localPath, int sheetIndex)
{
IWorkbook workbook;
using (FileStream file = new FileStream(localPath, FileMode.Open, FileAccess.Read))
{
workbook = WorkbookFactory.Create(file);
}
var importer = new Mapper(workbook);
var items = importer.Take<CustomExcelFormat>(sheetIndex);
foreach(var item in items)
{
var row = item.Value;
if (string.IsNullOrEmpty(row.EmailAddress))
continue;
UpdateUser(row);
}
DataContext.SaveChanges();
}
Now, admittedly, my code does not modify the Excel file itself. I am instead saving the data to a database using Entity Framework (that's why you see "UpdateUser" and "SaveChanges" in my example). But there is already a good discussion on SO about how to save/modify a file using NPOI.

Using OLE Query, it's quite simple (e.g. sheetName is Sheet1):
DataTable LoadWorksheetInDataTable(string fileName, string sheetName)
{
DataTable sheetData = new DataTable();
using (OleDbConnection conn = this.returnConnection(fileName))
{
conn.Open();
// retrieve the data using data adapter
OleDbDataAdapter sheetAdapter = new OleDbDataAdapter("select * from [" + sheetName + "$]", conn);
sheetAdapter.Fill(sheetData);
conn.Close();
}
return sheetData;
}
private OleDbConnection returnConnection(string fileName)
{
return new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + fileName + "; Jet OLEDB:Engine Type=5;Extended Properties=\"Excel 8.0;\"");
}
For newer Excel versions:
return new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + fileName + ";Extended Properties=Excel 12.0;");
You can also use Excel Data Reader an open source project on CodePlex. Its works really well to export data from Excel sheets.
The sample code given on the link specified:
FileStream stream = File.Open(filePath, FileMode.Open, FileAccess.Read);
//1. Reading from a binary Excel file ('97-2003 format; *.xls)
IExcelDataReader excelReader = ExcelReaderFactory.CreateBinaryReader(stream);
//...
//2. Reading from a OpenXml Excel file (2007 format; *.xlsx)
IExcelDataReader excelReader = ExcelReaderFactory.CreateOpenXmlReader(stream);
//...
//3. DataSet - The result of each spreadsheet will be created in the result.Tables
DataSet result = excelReader.AsDataSet();
//...
//4. DataSet - Create column names from first row
excelReader.IsFirstRowAsColumnNames = true;
DataSet result = excelReader.AsDataSet();
//5. Data Reader methods
while (excelReader.Read())
{
//excelReader.GetInt32(0);
}
//6. Free resources (IExcelDataReader is IDisposable)
excelReader.Close();
Reference: How do I import from Excel to a DataSet using Microsoft.Office.Interop.Excel?

Try to use this free way to this, https://freenetexcel.codeplex.com
Workbook workbook = new Workbook();
workbook.LoadFromFile(#"..\..\parts.xls",ExcelVersion.Version97to2003);
//Initialize worksheet
Worksheet sheet = workbook.Worksheets[0];
DataTable dataTable = sheet.ExportDataTable();

If you can restrict it to just (Open Office XML format) *.xlsx files, then probably the most popular library would be EPPLus.
Bonus is, there are no other dependencies. Just install using nuget:
Install-Package EPPlus

Try to use Aspose.cells library (not free, but trial is enough to read), it is quite good
Install-package Aspose.cells
There is sample code:
using Aspose.Cells;
using System;
namespace ExcelReader
{
class Program
{
static void Main(string[] args)
{
// Replace path for your file
readXLS(#"C:\MyExcelFile.xls"); // or "*.xlsx"
Console.ReadKey();
}
public static void readXLS(string PathToMyExcel)
{
//Open your template file.
Workbook wb = new Workbook(PathToMyExcel);
//Get the first worksheet.
Worksheet worksheet = wb.Worksheets[0];
//Get cells
Cells cells = worksheet.Cells;
// Get row and column count
int rowCount = cells.MaxDataRow;
int columnCount = cells.MaxDataColumn;
// Current cell value
string strCell = "";
Console.WriteLine(String.Format("rowCount={0}, columnCount={1}", rowCount, columnCount));
for (int row = 0; row <= rowCount; row++) // Numeration starts from 0 to MaxDataRow
{
for (int column = 0; column <= columnCount; column++) // Numeration starts from 0 to MaxDataColumn
{
strCell = "";
strCell = Convert.ToString(cells[row, column].Value);
if (String.IsNullOrEmpty(strCell))
{
continue;
}
else
{
// Do your staff here
Console.WriteLine(strCell);
}
}
}
}
}
}

Read from excel, modify and write back
/// <summary>
/// /Reads an excel file and converts it into dataset with each sheet as each table of the dataset
/// </summary>
/// <param name="filename"></param>
/// <param name="headers">If set to true the first row will be considered as headers</param>
/// <returns></returns>
public DataSet Import(string filename, bool headers = true)
{
var _xl = new Excel.Application();
var wb = _xl.Workbooks.Open(filename);
var sheets = wb.Sheets;
DataSet dataSet = null;
if (sheets != null && sheets.Count != 0)
{
dataSet = new DataSet();
foreach (var item in sheets)
{
var sheet = (Excel.Worksheet)item;
DataTable dt = null;
if (sheet != null)
{
dt = new DataTable();
var ColumnCount = ((Excel.Range)sheet.UsedRange.Rows[1, Type.Missing]).Columns.Count;
var rowCount = ((Excel.Range)sheet.UsedRange.Columns[1, Type.Missing]).Rows.Count;
for (int j = 0; j < ColumnCount; j++)
{
var cell = (Excel.Range)sheet.Cells[1, j + 1];
var column = new DataColumn(headers ? cell.Value : string.Empty);
dt.Columns.Add(column);
}
for (int i = 0; i < rowCount; i++)
{
var r = dt.NewRow();
for (int j = 0; j < ColumnCount; j++)
{
var cell = (Excel.Range)sheet.Cells[i + 1 + (headers ? 1 : 0), j + 1];
r[j] = cell.Value;
}
dt.Rows.Add(r);
}
}
dataSet.Tables.Add(dt);
}
}
_xl.Quit();
return dataSet;
}
public string Export(DataTable dt, bool headers = false)
{
var wb = _xl.Workbooks.Add();
var sheet = (Excel.Worksheet)wb.ActiveSheet;
//process columns
for (int i = 0; i < dt.Columns.Count; i++)
{
var col = dt.Columns[i];
//added columns to the top of sheet
var currentCell = (Excel.Range)sheet.Cells[1, i + 1];
currentCell.Value = col.ToString();
currentCell.Font.Bold = true;
//process rows
for (int j = 0; j < dt.Rows.Count; j++)
{
var row = dt.Rows[j];
//added rows to sheet
var cell = (Excel.Range)sheet.Cells[j + 1 + 1, i + 1];
cell.Value = row[i];
}
currentCell.EntireColumn.AutoFit();
}
var fileName="{somepath/somefile.xlsx}";
wb.SaveCopyAs(fileName);
_xl.Quit();
return fileName;
}

I used Office's NuGet Package: DocumentFormat.OpenXml and pieced together the code from that component's doc site.
With the below helper code, was similar in complexity to my other CSV file format parsing in that project...
public static async Task ImportXLSX(Stream stream, string sheetName) {
{
// This was necessary for my Blazor project, which used a BrowserFileStream object
MemoryStream ms = new MemoryStream();
await stream.CopyToAsync(ms);
using (var document = SpreadsheetDocument.Open(ms, false))
{
// Retrieve a reference to the workbook part.
WorkbookPart wbPart = document.WorkbookPart;
// Find the sheet with the supplied name, and then use that
// Sheet object to retrieve a reference to the first worksheet.
Sheet theSheet = wbPart?.Workbook.Descendants<Sheet>().Where(s => s?.Name == sheetName).FirstOrDefault();
// Throw an exception if there is no sheet.
if (theSheet == null)
{
throw new ArgumentException("sheetName");
}
WorksheetPart wsPart = (WorksheetPart)(wbPart.GetPartById(theSheet.Id));
// For shared strings, look up the value in the
// shared strings table.
var stringTable =
wbPart.GetPartsOfType<SharedStringTablePart>()
.FirstOrDefault();
// I needed to grab 4 cells from each row
// Starting at row 11, until the cell in column A is blank
int row = 11;
while (true) {
var accountNameCell = GetCell(wsPart, "A" + row.ToString());
var accountName = GetValue(accountNameCell, stringTable);
if (string.IsNullOrEmpty(accountName)) {
break;
}
var investmentNameCell = GetCell(wsPart, "B" + row.ToString());
var investmentName = GetValue(investmentNameCell, stringTable);
var symbolCell = GetCell(wsPart, "D" + row.ToString());
var symbol = GetValue(symbolCell, stringTable);
var marketValue = GetCell(wsPart, "J" + row.ToString()).InnerText;
// DO STUFF with data
row++;
}
}
}
private static string? GetValue(Cell cell, SharedStringTablePart stringTable) {
try {
return stringTable.SharedStringTable.ElementAt(int.Parse(cell.InnerText)).InnerText;
} catch (Exception) {
return null;
}
}
private static Cell GetCell(WorksheetPart wsPart, string cellReference) {
return wsPart.Worksheet.Descendants<Cell>().Where(c => c.CellReference.Value == cellReference)?.FirstOrDefault();
}

How to convert xml to excel file programmatically

I have a xml document holding a small data for my project where I want to convert my xml to an excel file (microsoft office excel 2003 and over)
How can I do this programmatically?

It can be achieved by using Microsoft.Office.Interop.Excel as shown below:
First of all declare these necessary references.
using System;
using System.IO;
using System.Reflection;
using System.Runtime.InteropServices;
using Microsoft.Office.Tools.Excel;
using Microsoft.VisualStudio.Tools.Applications.Runtime;
using Excel = Microsoft.Office.Interop.Excel;
using Office = Microsoft.Office.Core;
using System.Diagnostics;
using Microsoft.Win32;
Than create excel app as shown:
Excel.Application excel2; // Create Excel app
Excel.Workbook DataSource; // Create Workbook
Excel.Worksheet DataSheet; // Create Worksheet
excel2 = new Excel.Application(); // Start an Excel app
DataSource = (Excel.Workbook)excel2.Workbooks.Add(1); // Add a Workbook inside
string tempFolder = System.IO.Path.GetTempPath(); // Get folder
string FileName = openFileDialog1.FileName.ToString(); // Get xml file name
After that use below code in a loop to ensure all items in xml file are copied
// Open that xml file with excel
DataSource = excel2.Workbooks.Open(FileName, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value);
// Get items from xml file
DataSheet = DataSource.Worksheets.get_Item(1);
// Create another Excel app as object
Object xl_app;
xl_app = GetObj(1, "Excel.Application");
Excel.Application xlApp = (Excel.Application)xl_app;
// Set previous Excel app (Xml) as ReportPage
Excel.Application ReportPage = (Excel.Application)System.Runtime.InteropServices.Marshal.GetActiveObject("Excel.Application");
// Copy items from ReportPage(Xml) to current Excel object
Excel.Workbook Copy_To_Excel = ReportPage.ActiveWorkbook;
Now we have an Excel object named as Copy_To_Excel that contains all items in Xml..
We can save and close the Excel object with the name we want..
Copy_To_Excel.Save("thePath\theFileName");
Copy_To_Excel.Close();

If you have control over the XML generated, just generate an XML Spreadsheet file (the XML file standard for Excel 2002 and 2003).
These open natively in Excel, without having to change the extension. (To open by default in Excel, the file extension XML should be set to open with "XML Editor", which is an Office app that routes the XML file to Excel, Word, PowerPoint, InfoPath, or your external XML editor as needed. This is the default mapping when Office is installed, but it may be out of whack for some users, particularly devs who edit XML files in a text editor.)
Or, use the NPOI library to generate a native (97/2000 BIFF/XLS) Excel file rather than XML.

you can even read the XML file as string and use regular expressions to read the content between the tags and create a CSV file or use xpath expressions to read the XML file data and export to CSV file.

I know of no easy way to do code-based conversion from xml-based spreadsheet to xls/xlsx. But you might look into Microsoft Open Xml SDK which lets you work with xlsx. You might build xlsx spreadsheet and just feed it with your data. On the level of open-xml SDK it's like building xml file.

1.Fill the xml file into dataset,
2.convert dataset to excel by below method in asp.net
These are very simple methods.
public static void Convert(System.Data.DataSet ds, System.Web.HttpResponse response)
{
//first let's clean up the response.object
response.Clear();
response.Charset = "";
//set the response mime type for excel
response.ContentType = "application/vnd.ms-excel";
//create a string writer
System.IO.StringWriter stringWrite = new System.IO.StringWriter();
//create an htmltextwriter which uses the stringwriter
System.Web.UI.HtmlTextWriter htmlWrite = new System.Web.UI.HtmlTextWriter(stringWrite);
//instantiate a datagrid
System.Web.UI.WebControls.DataGrid dg = new System.Web.UI.WebControls.DataGrid();
//set the datagrid datasource to the dataset passed in
dg.DataSource = ds.Tables[0];
//bind the datagrid
dg.DataBind();
//tell the datagrid to render itself to our htmltextwriter
dg.RenderControl(htmlWrite);
//all that's left is to output the html
response.Write(stringWrite.ToString());
response.End();
}

For array elements separate with ',' comma and reuse the same column name
1) XML Functions
public static class XMLFunctions
{
public static List<Tuple<string, string>> GetXMlTagsAndValues(string xml)
{
var xmlList = new List<Tuple<string, string>>();
var doc = XDocument.Parse(xml);
foreach (var element in doc.Descendants())
{
// we don't care about the parent tags
if (element.Descendants().Count() > 0)
{
continue;
}
var path = element.AncestorsAndSelf().Select(e => e.Name.LocalName).Reverse();
var xPath = string.Join("/", path);
xmlList.Add(Tuple.Create(xPath, element.Value));
}
return xmlList;
}
public static System.Data.DataTable CreateDataTableFromXmlFile(string xmlFilePath)
{
System.Data.DataTable Dt = new System.Data.DataTable();
string input = File.ReadAllText(xmlFilePath);
var xmlTagsAndValues = GetXMlTagsAndValues(input);
var columnList = new List<string>();
foreach(var xml in xmlTagsAndValues)
{
if(!columnList.Contains(xml.Item1))
{
columnList.Add(xml.Item1);
Dt.Columns.Add(xml.Item1, typeof(string));
}
}
DataRow dtrow = Dt.NewRow();
var columnList2 = new Dictionary<string, string>();
foreach (var xml in xmlTagsAndValues)
{
if (!columnList2.Keys.Contains(xml.Item1))
{
dtrow[xml.Item1] = xml.Item2;
columnList2.Add(xml.Item1, xml.Item2);
}
else
{ // Here we are using the same column but appending the next value
dtrow[xml.Item1] = columnList2[xml.Item1] + "," + xml.Item2;
columnList2[xml.Item1] = columnList2[xml.Item1] + "," + xml.Item2;
}
}
Dt.Rows.Add(dtrow);
return Dt;
}
}
2) Full Excel class
using Microsoft.Office.Interop.Excel;
using _Excel = Microsoft.Office.Interop.Excel;
public class Excel
{
string path = "";
Application excel = new _Excel.Application();
Workbook wb;
Worksheet ws;
public Range xlRange;
static bool saveChanges = false;
static int excelRow = 0;
static List<string> columnHeaders = new List<string>();
public Excel(string path, int Sheet = 1)
{
this.path = path;
wb = excel.Workbooks.Open(path);
ws = wb.Worksheets[Sheet];
xlRange = ws.UsedRange;
excelRow = 0;
columnHeaders = new List<string>();
}
public void SaveFile(bool save = true)
{
saveChanges = save;
}
public void Close()
{
wb.Close(saveChanges);
System.Runtime.InteropServices.Marshal.ReleaseComObject(wb);
excel.Quit();
}
public void XMLToExcel(string xmlFilePath)
{
var dt = XMLFunctions.CreateDataTableFromXmlFile(xmlFilePath);
AddDataTableToExcel(dt);
}
public void AddDataTableToExcel(System.Data.DataTable table)
{
// Creating Header Column In Excel
for (int i = 0; i < table.Columns.Count; i++)
{
if (!columnHeaders.Contains(table.Columns[i].ColumnName))
{
ws.Cells[1, columnHeaders.Count() + 1] = table.Columns[i].ColumnName;
columnHeaders.Add(table.Columns[i].ColumnName);
}
}
// Get the rows
for (int k = 0; k < table.Columns.Count; k++)
{
var columnNumber = columnHeaders.FindIndex(x => x.Equals(table.Columns[k].ColumnName));
ws.Cells[excelRow + 2, columnNumber + 1] = table.Rows[0].ItemArray[k].ToString();
}
excelRow++;
SaveFile(true);
}
}
3) Call it
var excel = new Excel(excelFilename);
foreach (var filePath in files)
{
excel.XMLToExcel(filePath);
}
excel.Close();
For array elements having appended incremented column names (ex. column_2)
Create Data Table From XmlFile Redone
public static System.Data.DataTable CreateDataTableFromXmlFile(string xmlFilePath)
{
System.Data.DataTable Dt = new System.Data.DataTable();
string input = File.ReadAllText(xmlFilePath);
var xmlTagsAndValues = GetXMlTagsAndValues(input);
var columnList = new List<string>();
foreach (var xml in xmlTagsAndValues)
{
if (!columnList.Contains(xml.Item1))
{
columnList.Add(xml.Item1);
Dt.Columns.Add(xml.Item1, typeof(string));
}
else
{
var columnName = xml.Item1;
do
{
columnName = columnName.Increment();
} while (columnList.Contains(columnName));
columnList.Add(columnName);
Dt.Columns.Add(columnName, typeof(string));
}
}
DataRow dtrow = Dt.NewRow();
var columnList2 = new Dictionary<string, string>();
foreach (var xml in xmlTagsAndValues)
{
if (!columnList2.Keys.Contains(xml.Item1))
{
dtrow[xml.Item1] = xml.Item2;
columnList2.Add(xml.Item1, xml.Item2);
}
else
{
var columnName = xml.Item1;
do
{
columnName = columnName.Increment();
} while (columnList2.Keys.Contains(columnName));
dtrow[columnName] = xml.Item2;
columnList2[columnName] = xml.Item2;
}
}
Dt.Rows.Add(dtrow);
return Dt;
}
String Extensions
public static class StringExtensions
{
public static string Increment(this string str)
{
if (!str.Contains("_"))
{
str += "_2";
return str;
}
var number = int.Parse(str.Substring(str.LastIndexOf('_') + 1));
var stringBefore = StringFunctions.GetUntilOrEmpty(str, "_");
return $"{stringBefore}_{++number}";
}
}
Using GetUntilOrEmpty

How to open an XML file in Excel 2003.
In short, you can simply open it by using File › Open. Then, when you select an XML file, you are prompted to select one of the following methods to import the XML data:
As an XML list
As a read-only workbook
Use the XML Source task pane

Can't you simply open it in Excel? I thought Excel recognized the suffix XML?