Convert CSV to Excel

OfficeIMO.Excel.Csv connects the CSV and Excel packages. CSV parsing stays in OfficeIMO.CSV and workbook writing stays in OfficeIMO.Excel, so neither package depends on the other unless you install the adapter.

dotnet add package OfficeIMO.Excel.Csv

Import a CSV file as an Excel table

By default the import detects the delimiter, infers column types, and creates a filterable table, so numbers and dates arrive as numbers and dates rather than text.

C#

using OfficeIMO.CSV;
using OfficeIMO.Excel;
using OfficeIMO.Excel.Csv;

using var book = ExcelDocument.Create();
ExcelCsvImportResult imported = book.ImportCsvFile("sales.csv", new ExcelCsvImportOptions {
    SheetName = "Sales",
    TableName = "Sales",
    ReaderOptions = new CsvReaderOptions { DetectDelimiter = true, InferSchema = true, SchemaSampleRows = 1000 }
});
Console.WriteLine($"Delimiter '{imported.Delimiter}', table {imported.TableName}");
book.Save("sales.xlsx");

PowerShell

Import-OfficeCsv -Path .\sales.csv -InferSchema | Export-OfficeExcel -Path .\sales.xlsx -Sheet Sales -TableName Sales

CLI

officeimo tabular convert sales.csv sales.xlsx
officeimo tabular convert sales-pl.csv sales.xlsx --delimiter ';'

Save a loaded CSV document as Excel

C#

using OfficeIMO.CSV;
using OfficeIMO.Excel.Csv;

CsvDocument csv = CsvDocument.Load("sales.csv");
csv.SaveAsExcel("sales-document.xlsx");

Export a worksheet to CSV

C#

using OfficeIMO.Excel;
using OfficeIMO.Excel.Csv;

using var book = ExcelDocument.Load("sales.xlsx");
book["Sales"].SaveAsCsv("sales-export.csv");

PowerShell

Import-OfficeExcel -Path .\sales.xlsx -Sheet Sales | Export-OfficeCsv -Path .\sales-export.csv

CLI

officeimo tabular convert sales.xlsx sales-export.csv --sheet Sales

Limits and reference

Limits: see the Excel CSV adapter row. Conversion reports list omitted headers and schema projection; set FailOnLoss in the export options to reject them before writing.

Reference: OfficeIMO.Excel.Csv API · OfficeIMO.CSV API