Convert Xlsx | Xlsb to Xlt | Xlam in .NET – Supercharge Your Spreadsheet Workflows with Spreadsheet Converter

using SpreadsheetConverter;

// 1️⃣ Load the license (replace with your actual file)
var license = new License();
license.SetLicense(@"C:\Licenses\SpreadsheetConverter.lic");

// 2️⃣ Define load options – source workbook
var loadOptions = new LoadOptions
{
InputFile = @"C:\Samples\Budget2025.xlsx"
};

// 3️⃣ Define save options – destination template
var saveOptions = new SpreadsheetSaveOptions
{
OutputFile = @"C:\Outputs\BudgetTemplate.xlt",
SaveFormat = FileFormatType.Xlt // Xlt = non‑macro template
};

// 4️⃣ Perform the conversion
SpreadsheetConverter.Process(loadOptions, saveOptions);

Console.WriteLine("✅ XLSX → XLT conversion succeeded.");

using SpreadsheetConverter;

// License activation (reuse the same instance if possible)
var license = new License();
license.SetLicense(@"C:\Licenses\SpreadsheetConverter.lic");

// Load the XLT template
var loadOptions = new LoadOptions
{
InputFile = @"C:\Samples\ReportTemplate.xlt"
};

// Save as binary XLSB
var saveOptions = new SpreadsheetSaveOptions
{
OutputFile = @"C:\Outputs\ReportBinary.xlsb",
SaveFormat = FileFormatType.Xlsb
};

SpreadsheetConverter.Process(loadOptions, saveOptions);

Console.WriteLine("✅ XLT → XLSB conversion succeeded.");

using SpreadsheetConverter;
using System;
using System.IO;
using System.Linq;

try
{
// 1️⃣ License validation
var license = new License();
license.SetLicense(@"C:\Licenses\SpreadsheetConverter.lic");

// 2️⃣ Define allowed extensions (input & output)
var allowed = new[]
{
".xlsx", ".xlsb", ".xlsm", ".xltm", ".xlam",
".xls", ".xlw", ".xml", ".xlt", ".dif"
};

// 3️⃣ Input verification
string inputPath = @"C:\Incoming\SourceFile.xlsm";
if (!File.Exists(inputPath))
throw new FileNotFoundException($"Input file not found: {inputPath}");

string inputExt = Path.GetExtension(inputPath).ToLower();
if (!allowed.Contains(inputExt))
throw new NotSupportedException($"Unsupported input format: {inputExt}");

// 4️⃣ Output verification
string outputPath = @"C:\Outgoing\Result.xlsx";
string outputExt = Path.GetExtension(outputPath).ToLower();
if (!allowed.Contains(outputExt))
throw new NotSupportedException($"Unsupported output format: {outputExt}");

// 5️⃣ Map extension → FileFormatType enum
FileFormatType Map(string ext) => ext switch
{
".xlsx" => FileFormatType.Xlsx,
".xlsb" => FileFormatType.Xlsb,
".xlsm" => FileFormatType.Xlsm,
".xltm" => FileFormatType.Xltm,
".xlam" => FileFormatType.Xlam,
".xls" => FileFormatType.Excel97To2003,
".xlw" => FileFormatType.Excel95,
".xml" => FileFormatType.SpreadsheetML,
".xlt" => FileFormatType.Xlt,
".dif" => FileFormatType.Dif,
_ => throw new NotSupportedException($"Extension {ext} has no mapping.")
};

// 6️⃣ Build load & save options
var loadOptions = new LoadOptions { InputFile = inputPath };
var saveOptions = new SpreadsheetSaveOptions
{
OutputFile = outputPath,
SaveFormat = Map(outputExt)
};

// 7️⃣ Execute conversion
SpreadsheetConverter.Process(loadOptions, saveOptions);
Console.WriteLine($"✅ Conversion succeeded: {outputPath}");
}
catch (Exception ex)
{
// Centralized logging – replace with Serilog/NLog/etc. as needed
Console.Error.WriteLine($"❌ Conversion failed: {ex.GetType().Name} – {ex.Message}");
// Optionally rethrow for upstream handling
// throw;
}

Parallel.ForEach(filePairs, new ParallelOptions { MaxDegreeOfParallelism = 4 }, pair =>
{
var load = new LoadOptions { InputFile = pair.In };
var save = new SpreadsheetSaveOptions
{
OutputFile = pair.Out,
SaveFormat = FileFormatType.Xlsb
};
SpreadsheetConverter.Process(load, save);
});

# 1️⃣ Add the NuGet package
dotnet add package SpreadsheetConverter

# 2️⃣ Obtain a trial license (no credit‑card needed)
# https://www.spreadsheetconverter.com/trial

# 3️⃣ Drop the *.lic* file into your project (copy to output folder).

# 4️⃣ Run any of the snippets above – compile and watch the conversion happen.