Read large Excel files using C# and OpenXML

introduce

Efficient reading of large Excel files can be challenging, especially when dealing with applications that require high performance and scalability. Microsoft's OpenXML SDK provides a powerful set of tools to handle Office documents (including Excel files) without installing Excel on the server. This article will guide you to efficiently read large Excel files using C# and OpenXML.

Why use OpenXML

OpenXML is an open standard for office documents (Word, Excel, PowerPoint) that allows the operation of these documents programmatically. Some of the benefits of using OpenXML include:

Performance: It operates directly on file streams without loading the entire document into memory.

Dependency-free: No need to install Microsoft Office.

Scalability: Great for server-side applications and batch processing.

Prerequisites

Before digging into the code, make sure you have the following.

Visual Studio or any C# IDE

.NET Framework or .NET Core SDK

OpenXML SDK: You can install it through NuGet using the command.

Install-Package 

Read large Excel files using OpenXML

Here is a step-by-step guide to using C# and OpenXML to read large Excel files.

1. Set up the project

Create a new C# console application.

Open Visual Studio and create a new console application (.NET Core or .NET Framework).

Install the OpenXML SDK through NuGet.

2. Open Excel file

First, you need to open the Excel file and access the worksheet you want to read. Use the following code to open an Excel file.

using ;
using ;
using System;
using ;

namespace ReadLargeExcelFile
{
    class Program
    {
        static void Main(string[] args)
        {
            string filePath = "path/to/your/large/";
            using (SpreadsheetDocument doc = (filePath, false))
            {
                WorkbookPart workbookPart = ;
                Sheet sheet = <Sheet>();
                WorksheetPart worksheetPart = (WorksheetPart)();

                IEnumerable<Row> rows = <SheetData>().Elements<Row>();

                foreach (Row row in rows)
                {
                    foreach (Cell cell in <Cell>())
                    {
                        string cellValue = GetCellValue(doc, cell);
                        (cellValue + " ");
                    }
                    ();
                }
            }
        }

        private static string GetCellValue(SpreadsheetDocument doc, Cell cell)
        {
            SharedStringTablePart stringTablePart = ;
            string value = ;

            if ( != null &&  == )
            {
                return [(value)].InnerText;
            }
            else
            {
                return value;
            }
        }
    }
}

3. Efficiently process large files

The above code reads the entire worksheet into memory, which may be inefficient for very large files. To handle large files more efficiently, consider processing files in chunks or using streaming techniques.

4. Optimize performance

To optimize performance, you can

Streaming files: Use streaming technology to process files in part, rather than loading the entire file into memory.

Parallel Processing: If your application allows you, you can process different parts of the file in parallel.

Efficient data structure: Use efficient data structures to store and process data.

Here is an example using streaming.

using ;
using ;
using System;
using ;

namespace ReadLargeExcelFile
{
    class Program
    {
        static void Main(string[] args)
        {
            string filePath = "path/to/your/large/";
            using (SpreadsheetDocument doc = (filePath, false))
            {
                WorkbookPart workbookPart = ;
                Sheet sheet = <Sheet>();
                WorksheetPart worksheetPart = (WorksheetPart)();

                OpenXmlReader reader = (worksheetPart);
                while (())
                {
                    if ( == typeof(Row))
                    {
                        Row row = (Row)();
                        foreach (Cell cell in <Cell>())
                        {
                            string cellValue = GetCellValue(doc, cell);
                            (cellValue + " ");
                        }
                        ();
                    }
                }
            }
        }

        private static string GetCellValue(SpreadsheetDocument doc, Cell cell)
        {
            SharedStringTablePart stringTablePart = ;
            string value = ;

            if ( != null &&  == )
            {
                return [(value)].InnerText;
            }
            else
            {
                return value;
            }
        }
    }
}

in conclusion

Reading large Excel files using C# and OpenXML provides a powerful solution for applications that require high performance and scalability. By following the practices outlined in this article, you can efficiently process large datasets stored in Excel files, making your applications more efficient and responsive. OpenXML operates Office documents without installing Office, making it an important tool in any developer toolkit.

This is the end of this article about using C# and OpenXML to read large Excel files. For more related C# OpenXML to read Excel content, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!