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General Information

Updated on May 11, 2026

RadSpreadProcessing's document model allows you to easily open and save files of different formats. This article will share more details on the supported formats, available format providers, the additional package references each provider requires and the Format Providers Manager.

Supported formats

The following table lists the supported formats:

Format	Description
`Xlsx`	Rich text format that exports the whole content of a workbook: worksheets, formula values, formatting, hyperlinks, etc.
`Xls`	Rich text format that exports the content of a workbook: worksheets, formula values, formatting, hyperlinks, etc. Supported in older applications. This format is not supported in Silverlight.
`Xlsm`	Rich text format that exports all that is included in the Xlsx format with the addition of macro instructions.
`Pdf` (export only)	Fixed format that preserves the content of a workbook in a manner independent from software or hardware.
`Csv` (comma separated)	Plain text format that saves the content of the cell in the active worksheet. The format strips all formatting and keeps only the result values of cells. These values are separated by a culture-dependent delimiter.
`Txt` (tab delimited)	Plain text format that preserves only the content of the cells in the active worksheet. The format does not save any formatting and keeps only the result values of the cells. These values are delimited via tabs.
`Json` (export only)	Structured text format that serializes worksheet data and metadata (values, number formats, named ranges, charts, active sheet info, etc.) to JSON. Styling is not preserved fully as in XLSX.
`DataTable`	Allows you to convert a `DataTable` from your database to a spreadsheet and vice versa.

In Q4 2024 Telerik Document Processing Libraries introduced a new timeout mechanism for importing and exporting documents. The Import and Export methods of all FormatProviders have a mandatory TimeSpan? timeout parameter after which the operation will be cancelled.

Format providers

The document model exposes separate format providers that work with each of the formats above:

XlsxFormatProvider for .xlsx files
XlsFormatProvider for .xls files
XlsmFormatProvider for .xlsm files
PdfFormatProvider for .pdf files (export only)
CsvFormatProvider for comma separated .csv files
TxtFormatProvider for tab delimited .txt files
DataTableFormatProvider for DataTable objects
JsonFormatProvider for .json files (export only)

Some FormatProviders require additional package references. Check them out in the Additional Package References section.

Import and Export methods

All of the listed providers implement the IWorkbookFormatProvider and IBinaryWorkbookFormatProvider interfaces and, thus, share a common API that enables import and export of files. To conform to the interfaces each of the providers implements two methods that, respectively, turn a Stream or byte[] into a workbook and save the contents of the workbook into a Stream or byte[]. In the IWorkbookFormatProvider interface methods and IBinaryWorkbookFormatProvider interface methods sections below you can see the interfaces' declaration and an example usage of the Import and Export methods.

IWorkbookFormatProvider interface methods

public interface IWorkbookFormatProvider
{
    string Name { get; }
    string FilesDescription { get; }
    IEnumerable<string> SupportedExtensions { get; }
    bool CanImport { get; }
    bool CanExport { get; }

    //Import and Export methods with Stream support
    void Export(Workbook workbook, Stream output, TimeSpan? timeout = null);
    Workbook Import(Stream input, TimeSpan? timeout = null);
}

Example: Use FormatProver's Import() and Export() methods with Stream array

string path = "MyWorkbook.xlsx";
Telerik.Windows.Documents.Spreadsheet.Model.Workbook workbook;
var formatProvider = new Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx.XlsxFormatProvider();

//Import
using (Stream input = new FileStream(path, FileMode.Open))
{
    workbook = formatProvider.Import(input, TimeSpan.FromSeconds(10));
}

//Export
using (Stream output = new FileStream(path, FileMode.Create))
{
    formatProvider.Export(workbook, output, TimeSpan.FromSeconds(10));
}

IBinaryWorkbookFormatProvider interface methods

public interface IBinaryWorkbookFormatProvider : IWorkbookFormatProvider
{
    //Overloading IWorkbookFormatProvider's Import and Export methods to support byte[]
    byte[] Export(Workbook workbook);
    Workbook Import(byte[] input);
}

Example: Use FormatProver's Import() and Export() methods with byte[] array

var path = "MyWorkbook.xlsx";
Telerik.Windows.Documents.Spreadsheet.Model.Workbook workbook;
var formatProvider = new Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx.XlsxFormatProvider();

//Import
byte[] fileAsByteArray = File.ReadAllBytes(path);
workbook = formatProvider.Import(fileAsByteArray, TimeSpan.FromSeconds(10));

//Export
byte[] workbookAsByteArray = formatProvider.Export(workbook, TimeSpan.FromSeconds(10));

For more examples of importing and exporting workbooks check out the Import/Load and Export/Save RadSpreadProcessing Workbook knowledge base article.

Additional package references

Unlike the CsvFormatProvider, TxtFormatProvider, and DataTableFormatProvider classes, the other RadSpreadProcessing format providers require references to additional packages:

Format Provider	Required Package
`XlsxFormatProvider` and `XlsmFormatProvider`	`Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml`
`PdfFormatProvider` (export only)	`Telerik.Windows.Documents.Spreadsheet.FormatProviders.Pdf`
`XlsFormatProvider`	`Telerik.Windows.Documents.Spreadsheet.FormatProviders.Xls`
`JsonFormatProvider` (export only)	`Telerik.Windows.Documents.Spreadsheet.FormatProviders.Json`

*As of Q2 2025 the Zip Library will no longer be used as an internal dependency in the rest of the Document Processing Libraries - PdfProcessing, WordsProcessing, SpreadProcessing, SpreadStreamProcessing. It will be replaced by the System.IO.Compression. We will continue to ship the Telerik Zip Library as a standalone library so clients can still use it separately.

Format Providers Manager

The document model of RadSpreadProcessing also contains a WorkbookFormatProvidersManager class, which exposes a whole set of useful static methods. The manager also allows you to specify a set of format providers you would like to use. Then you can import and export a file leaving the manager to choose the appropriate format provider to use. You only need to specify the extension of the file that you open or save.

More information on the Format Providers Manager and the WorkbookFormatProvidersManager class can be found in the dedicated Format Providers Manager article.