Using XlsFormatProvider

Updated on Jun 16, 2026

XlsFormatProvider makes it easy to import and export XLS (Excel 97-2003 Workbook) files. The functionality is available starting with R3 2020.

The XlsFormatProvider requires references to the following packages:

• Telerik.Windows.Documents.Spreadsheet.FormatProviders.Xls for .NET Framework projects
• Telerik.Documents.Spreadsheet.FormatProviders.Xls for .NET Standard projects

After you reference these packages, create an instance of the XlsFormatProvider to import and export Excel 97-2003 Workbook files. This provider appears in the Telerik.Windows.Documents.Spreadsheet.FormatProviders.Xls namespace. XlsFormatProvider implements the IWorkbookFormatProvider interface, which in turn appears in Telerik.Windows.Documents.Spreadsheet.FormatProviders. Depending on whether you work with the concrete class or the interface, include either the first or both namespaces.

For more examples and application scenarios of importing and exporting a workbook to various formats, see the Import/Load and Export/Save RadSpreadProcessing Workbook knowledge base article.

Import

The following example shows how to import an XLS file through a FileStream. The code verifies that a file with the specified name exists. The sample creates an XlsFormatProvider instance and passes a FileStream to its Import() method.

Example 1: Import XLS (Excel 97-2003 Workbook) File

C#

string fileName = "SampleFile.xls";
if (!File.Exists(fileName))
{
    throw new FileNotFoundException(String.Format("File {0} was not found!", fileName));
}

Telerik.Windows.Documents.Spreadsheet.Model.Workbook workbook;
Telerik.Windows.Documents.Spreadsheet.FormatProviders.Xls.XlsFormatProvider formatProvider = new Telerik.Windows.Documents.Spreadsheet.FormatProviders.Xls.XlsFormatProvider();

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

Export

The following example demonstrates how to export an existing workbook to an XLS file. The snippet creates a new workbook with a single worksheet. The example then creates an XlsFormatProvider instance and invokes its Export() method. The Export() method accepts a parameter of type Stream so you can work with any of its inheritors.

Example 2: Export Spreadsheet Document to XLS (Excel 97-2003 Workbook) File

C#

Telerik.Windows.Documents.Spreadsheet.Model.Workbook workbook = new Telerik.Windows.Documents.Spreadsheet.Model.Workbook();
workbook.Worksheets.Add();
string fileName = "SampleFile.xls";

Telerik.Windows.Documents.Spreadsheet.FormatProviders.Xls.XlsFormatProvider formatProvider = new Telerik.Windows.Documents.Spreadsheet.FormatProviders.Xls.XlsFormatProvider();

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

Example 3: Export Spreadsheet Document to a Stream and byte[]

C#

Telerik.Windows.Documents.Spreadsheet.Model.Workbook workbook = new Telerik.Windows.Documents.Spreadsheet.Model.Workbook();
workbook.Worksheets.Add();

Telerik.Windows.Documents.Spreadsheet.FormatProviders.Xls.XlsFormatProvider formatProvider = new Telerik.Windows.Documents.Spreadsheet.FormatProviders.Xls.XlsFormatProvider();

byte[] bytes;
using (MemoryStream output = new MemoryStream())
{
    formatProvider.Export(workbook, output, TimeSpan.FromSeconds(10));
    bytes = output.ToArray();
}

*This documentation is neither affiliated with, nor authorized, sponsored, or approved by, Microsoft Corporation.

See Also

• Import/Load and Export/Save RadSpreadProcessing Workbook
• Timeout Mechanism