Develop Reference

Database (Excel) Access Speed - Using Open XML SDK in Visual Studio C# (DOM Approach)

I mostly write number-crunching programs using Visual Studio C# (2019) where I am simply taking input data, calculating results and displaying it. No complicated Network or Internet programming. Think first or second college level programming coarse from the early 1990's.
For inputs I was reading in data from an excel file using the following directive:
using Excel = Microsoft.Office.Interop.Excel;
This proved to be very slow when executing the program. I then learned this way of accessing an Excel file is no longer supported and has been superseded by Open XML SDK. Please see the following link to the Microsoft Dev Center page:
https://learn.microsoft.com/en-us/office/open-xml/how-to-parse-and-read-a-large-spreadsheet
For what I want to do the Document Object Model(DOM) approach seems most appropriate for the thousands of individual excel cells I want to read as input data. However, the Microsoft Dev Center is certainly not the most user-friendly resource and the code example provided for reading an Excel file using this DOM approach is writing to a console which I'm not using. I never did get my code to work.
Long and short of it is, I got my code working using the GetCellValue Method:
https://learn.microsoft.com/en-us/office/open-xml/how-to-retrieve-the-values-of-cells-in-a-spreadsheet
However, this 'GetCellValue' method is still taking way too long. I need to read in thousands or tens of thousands of Excel input data cells in seconds or fractions of seconds not 20 seconds to a minute.
I think if I had an example of the DOM method reading in Excel data to an Array Variable (instead of writing to the console) it would help. Can anyone provide an example of such code?
Below I have included my code example where I modified the DOM approach code copied from the Microsoft Office Dev Center to write values from a source Excel File to a DataGrid instead of the Console used by the Dev Center code:
C#
// The DOM approach.
// Note that the code below works only for cells that contain numeric values.
//
public void ReadExcelFileDOM(string fileName)
{
using (SpreadsheetDocument spreadsheetDocument = SpreadsheetDocument.Open(fileName, false))
{
WorkbookPart workbookPart = spreadsheetDocument.WorkbookPart;
WorksheetPart worksheetPart = workbookPart.WorksheetParts.First();
SheetData sheetData = worksheetPart.Worksheet.Elements<SheetData>().First();
DataGridView_Vessel.Rows.Clear();
DataGridView_Vessel.Refresh();
string text;
int File_Row = 0;
int File_Cell = 0;
foreach (Row r in sheetData.Elements<Row>())
{
DataGridView_Vessel.Rows.Add();
foreach (Cell c in r.Elements<Cell>())
{
if (c.CellValue == null)
{
File_Cell++;
//continue;
}
else
{
text = c.CellValue.Text;
if(File_Cell<12)
{
DataGridView_Vessel.Rows[File_Row].Cells[File_Cell].Value = text;
}
File_Cell++;
}
}
File_Row++;
}
//Console.WriteLine();
//Console.ReadKey();
}
}

Convert Excel (xlsx) to XML with C# and BizTalk

I have looked at most of the topics on this forum regarding similar questions but haven't found exactly what I am looking for.
I am trying to write a pipeline component for BizTalk 2013 R2 using C# to simply convert an incoming Excel 2010 .xlsx file to it's bare/base XML representation.
I do not want to run any templates against it or XLST transform it or anything like that. I simply just want to return the underlying XML representation of said spreadsheet as is.
It seems like this should be a very easy task but I can't figure out how to do it at all.
Everything I've found requires working with DataTables and looping through rows and cells (via OpenXML) to output a specific XML representation that is more human readable but that isn't what I want.
I want the actual Microsoft XML representation of that spreadsheet.
Any help would be greatly appreciated.

OK, figured it out without having to do any unzipping of the file.
If you use the SAX approach to loading the worksheet into an OpenXmlReader found here:
https://msdn.microsoft.com/en-us/library/office/gg575571(v=office.15).aspx
You can then use the reader to get the OuterXml like so:
using (SpreadsheetDocument spreadSheetDocument = SpreadsheetDocument.Open(filepath, false))
{
WorkbookPart wbPart = spreadSheetDocument.WorkbookPart;
OpenXmlReader reader = OpenXmlReader.Create(wbPart);
while (reader.Read())
{
if (reader.ElementType == typeof(Sheet))
{
Sheet sheet = (Sheet)reader.LoadCurrentElement();
WorksheetPart wsPart = (WorksheetPart)(wbPart.GetPartById(sheet.Id));
OpenXmlReader wsReader = OpenXmlReader.Create(wsPart);
while (wsReader.Read())
{
if(wsReader.ElementType == typeof(Worksheet))
{
Worksheet wsPartXml = (Worksheet)wsReader.LoadCurrentElement();
Console.WriteLine(wsPartXml.OuterXml + "\n");
}
}
}
}
Console.ReadKey();
}

read/write a simple excel file using c#

I'm trying to find a simple way of writing an excel file in c#, but everything that I've found on thank you for your help.

You have two options available to you
The First is to use Interop Assemblies here is a link to some sample code on how to do that Write Data to Excel using C#
The Second option is to use OLEDB. There is some information on Stack Overflow on that here

Use epplus as mentioned above,It makes it really simple. This is the code for a spread sheet i created with it today.
using (ExcelPackage pck = new ExcelPackage())
{
//Give the worksheet a name
ExcelWorksheet ws = pck.Workbook.Worksheets.Add("Inventory as of " + DateTime.Now.ToString("MM/dd/yyyy"));
//dt is a datable that i am turning into an excel document
ws.Cells["A1"].LoadFromDataTable(dt, true);
//Format the header columns(Color,Pattern,etc.)
using (ExcelRange rng = ws.Cells["A1:AA1"])
{
rng.Style.Font.Bold = true;
rng.Style.Fill.PatternType = ExcelFillStyle.Solid; //Set Pattern for the background to Solid
rng.Style.Fill.BackgroundColor.SetColor(Color.FromArgb(79, 129, 189)); //Set color to dark blue
rng.Style.Font.Color.SetColor(Color.White);
}
//End Format the header columns
//Give the file details(ie. filename, etc.)
Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
Response.AddHeader("content-disposition", "attachment;filename=Inventory Report " + DateTime.Now.ToString("MM/dd/yyyy") + ".xlsx");
//Write the file
Response.BinaryWrite(pck.GetAsByteArray());
Response.End();
pck.Save();
}

what you would need is epplus, this will help you to create 2007+ excel file
not compatible with 2003 and under

There is no really easy way depending of the version of excel file you want to write. If you want to go for xls you won't have much options than using Excel interop which would also have the dependency to have Excel installed.
The newer version offers some more options as it is just XML in the background. You can choose yourself how to create it, either yourself, some libraries or again Interop.
If you just want to display a table without any styling, there was (afair) a way to write csv file and excel can open it quite well (depending on the data types you want to use in it).

Read Data from Excel Worksheet in c#?

I need some way to read worksheets from an Excel file, then select what it's important, and put all the Data in a Database.
It's a job for one time only. It's an old excel file with information, that have to be passed to a Database, and which will work with an application that i have developed.
I saw many examples but i am not understanding well how it works, and which way is the best to do this type of work.
My idea is to develop some application in c# that to this process.

LINQ may work and would be preferable for a relatively simple table.
A traditional approach would be to use COM Interop. Here's a Microsoft page about to work with Excel using COM interop (it is for spreadsheet creation, but the principles are the same - just use different API methods to open and read data):
http://msdn.microsoft.com/en-us/library/ms173186(v=vs.80).aspx

I strongly suggest using a linq provider to connect to excel. This should make it very easy to query for the information you are looking for. Once you have it, inserting into the database should be easy.
http://code.google.com/p/linqtoexcel/

I've used this before and it works well.
http://exceldatareader.codeplex.com/
had an example handy...
using (FileStream fileStream = File.Open(inputFilenames[0], FileMode.Open, FileAccess.Read))
{
IExcelDataReader excelReader;
if (Path.GetExtension(inputFilenames[0]) == ".xls")
excelReader = Factory.CreateReader(fileStream, ExcelFileType.Binary);
else
excelReader = Factory.CreateReader(fileStream, ExcelFileType.OpenXml);
excelReader.NextResult();
while (excelReader.Name != this.Worksheet)
excelReader.NextResult();
while (excelReader.Read())
{
if (FirstRowHasColumnNames)
{
FirstRowHasColumnNames = false;
}
else
{
//do stuff
var test = GetColumnData(excelReader, 1);
}
}
this.Save(outputFilename);
}

Read Data from Excel Worksheet in c#? I got the Exact solution here visit
http://microsoftdotnetsolutions.blogspot.in/2012/12/get-excel-sheet-data.html

Slow Performance When Reading Excel

I want to read excel file but in this way is too slow. What pattern should I use to read excel file faster. Should I try csv ?
I am using the following code:
ApplicationClass excelApp = excelApp = new ApplicationClass();
Workbook myWorkBook = excelApp.Workbooks.Open(#"C:\Users\OWNER\Desktop\Employees.xlsx");
Worksheet mySheet = (Worksheet)myWorkBook.Sheets["Sheet1"];
for (int row = 1; row <= mySheet.UsedRange.Rows.Count; row++)
{
for (int col = 1; col <= mySheet.UsedRange.Columns.Count; col++)
{
Range dataRange = (Range)mySheet.Cells[row, col];
Console.Write(String.Format(dataRange.Value2.ToString() + " "));
}
Console.WriteLine();
}
excelApp.Quit();

The reason your program is slow is because you are using Excel to open your Excel files. Whenever you are doing anything with the file you have to do a COM+ interop, which is extremely slow, as you have to pass memory across two different processes.
Microsoft has dropped support for reading .xlsx files using Excel interop. They released the OpenXML library specifically for this reason.
I suggest you use a wrapper library for using OpenXML, since the API is pretty hairy. You can check out this SO for how to use it correctly.
open xml reading from excel file

You're accessing Excel file through excel interop. By doing reads cell by cell you're doing a lot of P/Invoke's which is not very performant.
You can read data in ranges, not cell by cell. This loads the data into memory and you could iterate it much faster. (Eg. try to load column by column.)
BTW: You could use some library instead like http://epplus.codeplex.com which reads excel files directly.

Excel Data Reader
Lightweight and very fast if reading is your only concern.