LargeXlsx 0.0.3

LargeXlsx - Minimalistic .net library to write large XLSX files

This is a minimalistic library, written in C# targeting .net standard 2.0, providing a tiny layer above Microsoft's Office Open XML library to facilitate creation of very large Excel files in XLSX format.

This library provides simple primitives to write data in a streamed manner, so that potentially huge files can be created while consuming a low, constant amount of memory.

Supported features

Currently the library supports:

• cells containing inline strings
• cells containing numeric (double) values
• multiple sheets
• merged cells (warning: their reference is kept in memory until a sheet is complete)
• split panes, a.k.a. frozen rows and columns
• basic styling: font face, size, and color; solid background color; top-right-bottom-left cell borders; numeric formatting

Example

To create a simple single-sheet Excel document:

using (var stream = new FileStream("Simple.xlsx", FileMode.Create))
using (var largeXlsxWriter = new LargeXlsxWriter(stream))
{
    var whiteFont = largeXlsxWriter.Stylesheet.CreateFont("Calibri", 11, "ffffff", bold: true);
    var blueFill = largeXlsxWriter.Stylesheet.CreateSolidFill("004586");
    var headerStyle = largeXlsxWriter.Stylesheet.CreateStyle(whiteFont, blueFill, LargeXlsxStylesheet.GeneralNumberFormat, LargeXlsxStylesheet.NoBorder);

    largeXlsxWriter.BeginSheet("Sheet1")
        .BeginRow().WriteInlineString("Col1", headerStyle).WriteInlineString("Col2", headerStyle).WriteInlineString("Col3", headerStyle)
        .BeginRow().WriteInlineString("Row2").Write(42).Write(-1)
        .BeginRow().WriteInlineString("Row3").SkipColumns(1).Write(1234)
        .SkipRows(2)
        .BeginRow().WriteInlineString("Row6").AddMergedCell(1, 2).SkipColumns(1).Write(3.14159265359);
}

The output is like:

Known issues

On .net core there is an issue on System.IO.Packaging (used by the Open XML SDK to write XLSX's zip packages) that causes memory consumption to be proportional to the amount of data written, instead of being low and constant. Unfortunately, this kind of defeats the purpose of this library when targeting .net core. The issue is not present on .net framework.

License

Permissive, 2-clause BSD style

LargeXlsx - Minimalistic .net library to write large XLSX files

Copyright 2020 Salvatore ISAJA

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

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