Essential XlsIO is a .NET class library that can read and write Microsoft Excel files. It includes a comprehensive API similar to the Microsoft Office Automation libraries. It does not have any external dependencies and can be used on systems that do not have Microsoft Excel installed.

Conceptual Overview Diagram

Why Syncfusion

Blazing Fast Performance

Optimized for usage in a server environment where speed and low memory usage is critical. It works much faster and consumes lesser memory when compared to Office automation libraries.

No Server Deployment Fees

There are no distribution fees, per-server licensing fees, or royalties, making XlsIO very cost-effective.

Easy Migration from Office Automation

Very easy to migrate existing Office automation code to XlsIO since the APIs are very similar.

Compatible with Excel Versions 97 to 2016

Read and write all popular Excel file formats including XLS and XLSX. You can even open a file in one format and save it back to another format.

Powerful and Comprehensive API

The comprehensive API makes it possible to create richly formatted Excel files with elements like text, numbers, formatting, images, charts and pivot tables. It is also possible to extract any desired piece of information from an existing workbook.

Start Reports with Excel and Finish with XlsIO

Design reports using Microsoft Excel and use XlsIO to dynamically populate it with data. You can then save the final report to an Excel file or export it to other supported formats like PDF.

Key Features

Import and Export Data

Easily import data from all the common data sources like arrays, data tables and business objects into an Excel worksheet. Data in an existing worksheet can also be exported to the common data sources.

Efficient Calculations

The built-in calculation engine can quickly evaluate formula cell values during runtime. It has support for over 180 Excel functions.

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Template Markers

Excel templates are dynamically replaced with data when processed using XlsIO.

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Excel Charting

Create and manipulate all types of Excel charts with elements like chart title, legend, axis title, data labels, line styles, etc. These charts can also be converted to images using just a few lines of code.

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Data Validation

Cell data validations can be applied with operators, alert messages, custom formulas and drop-down lists.

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Conditional Formatting

Visually highlight important values with data bars, icon sets and color scales based on conditions.

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Row Column Manipulation

Performs various cell level operations like resizing rows and columns, hiding and showing rows and columns, adding or deleting rows and columns, grouping and ungrouping, sub-totaling, etc.

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Pivot Tables

Create and manipulate pivot tables and pivot charts in just a few lines of code. General filter options such as page filters, row filters and column filters with various pivot table visibility settings are supported.

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Convert Excel document to PDF, HTML and images. Excel charts can also be converted to images.

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Formatting Options

Supports various formatting options like number formats, alignments, font settings, borders, colors, rich text, etc. that helps make data more readable.

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Perform data sorting based on cell value, cell color and font color using multiple sorting algorithms.

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Create custom styles or apply built-in styles to cell ranges. Built-in styles can also be applied for tables.

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Supports various filter options like Top, Top10, Percent, etc. along with different filter data types.


Read and write password protected Excel documents. Enable and disable workbook and worksheet protections along with locking cells.

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Create and manipulate autoshapes, comments, text boxes, combo boxes, check boxes and option buttons.

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Page Setup

Enable page settings like orientation, paper size, scaling, margins, print area, print titles, header and footer, etc.

Feature Matrix

Workbook Features XLS XLSX
Create an Excel workbook from scratch or modify an existing workbook
Open an existing Excel workbook from file system or stream
Save Excel workbook to a local file, stream or stream it to the client browser
Read worksheets on demand when Excel file contains multiple worksheets
Hide and unhide worksheets
Add or extract custom XML documents
Add or modify document properties
Import and Export XLS XLSX
Import data from DataTable, DataColumn, DataView, Array and Business Objects to worksheet
Import data into a pre-formatted template using Template Markers
Importing large amounts of data with minimal memory consumption can be achieved using the import on save option
Export data from worksheet to DataTable
Imports data from various external sources like Microsoft Access, SQL Server and Excel, which maintain the connection to refresh data dynamically
Formulas XLS XLSX
Read and write Excel formulas
Add or modify named ranges in workbook and worksheet levels
Performs calculation for a range of cells using named ranges
Apply or modify Excel formula auditing settings
Enable automatic and manual calculation options
Creation and manipulation of Excel 2D charts
Creation and manipulation of Excel 3D charts
Creation and manipulation of custom charts
Creation and manipulation of Sparklines NA
Pivot Tables
Creation and manipulation of pivot tables (While saving as XLS format, the pivot table is preserved as-is from the input XLS file)
Apply various pivot table settings like page filter, row filter and column filter (While saving as XLS format, pivot table is preserved as-is from the input XLS file)
Supports pivot table settings such as visibility of field list, collapse button, field caption and field option, header captions, etc.
Worksheet Features XLS XLSX
Creation and manipulation of conditional formatting (Supports Icon Sets, Data bars, Color Scales and Specific Date in XLSX)
Auto fit or resize rows and columns
Apply or modify number formats
Apply or modify fill settings
Apply or modify font settings
Apply or modify cell border settings
Apply or modify all the cell text alignments
Excel 2007 themes
Add or copy worksheets within or across workbooks
Copy a range to another range across worksheets
Copy a range with different copy options
Move a range to another range across worksheets
Creation and manipulation of data validation
Apply or modify auto-filters to filter worksheet data
Apply or modify data sorting
Find and replace data
Row/Column Manipulation
Apply and modify view settings to freeze, unfreeze and split panes
Hide and unhide rows and columns
Merge and unmerge cells
Insertion and deletion of images in worksheets
Apply or modify background image in a worksheet
Add, remove and modify hyperlinks
Group or ungroup rows and columns
Add or modify subtotals of grouped data
Addition and deletion of OLE objects
Open and save encrypted and decrypted documents
Protect and unprotect workbook
Protect and unprotect worksheets
Lock and unlock cells for write protection
Page Setup
Set and get header and footer settings
Apply and modify horizontal and vertical page breaks
Apply and modify custom page breaks
Apply various page setup options like paper size, orientation, scaling, margins, etc.
Apply print settings
Creation and manipulation of auto shapes
Creation and manipulation of check boxes
Creation and manipulation of combo boxes
Creation and manipulation of comments
Creation and manipulation of text boxes
Preserve Macros
Conversion XLS XLSX
Converts Excel document to PDF
Converts an entire Excel worksheet into a single image
Converts specific range of an Excel worksheet into a single image
Converts Excel charts to images (.NET framework 4.0 and above)

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