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Excel-Xlsx (OOXML) Export

XLSX is well-known format for Microsoft Excel documents that was introduced by Microsoft with the release of Microsoft Office 2007 and is based on the Office Open XML (OOXML) standard ECMA-376. the new format is a zip package that contains a number of XML files. The underlying structure and files can be examined by simply unzipping the .xlsx file.

Telerik ASP.NET AJAX Controls support this format since Q3 2014 by utilizing the Telerik Document Processing Libraries (DPL).

The DPL is included in the Telerik UI for ASP.NET AJAX suite, see Included Assemblies .

Required Assemblies

The assemblies that must be referenced in order to export RadGrid to Excel are:

  • Telerik.Windows.Documents.Core.dll
  • Telerik.Windows.Documents.Spreadsheet.dll
  • Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.dll
  • Telerik.Windows.Zip.dll

More information about the assemblies and how to reference them in your project can be found in the Included assemblies help article.


In order to use this export format, be sure to reference the DPL assemblies and change the Excel-Format property to Xlsx within the ExportSettings element.


<telerik:RadGrid ID="RadGrid1" runat="server">
        <Excel Format="Xlsx" />

Export events

Server-Side events triggered for the Biff format.

  • OnInfrastructureExporting: This event is triggered when the Export Structure is ready. It can be used to change the Export Structure before exporting. The Export Structure can be accessed from the Event argument - (Telerik.Web.UI.ExportInfrastructure.ExportStructure)e.ExportStructure

  • OnGridExporting: This event is triggered when the Grid is exporting regardless of the Export Format. It can also be used to access the output, however, unlike in the OnInfrastructureExporting event, the output returns a string - (string)e.ExportOutput.

  • OnExcelExportCellFormatting: This is event is triggered when the Grid export functionality formats the cell. It fires for every cell and can be used to apply additional styles to them.

For more details, check out the Styling section.

Customizing the Export Output

Formatting Cell Values

When you set DataFormatString of RadGrid columns, the format will be applied to the exported file.

Note that only the custom numeric format strings (Example 1) will work because in most scenarios they match the Microsoft Excel's custom numeric format.

The built-in .NET standard numeric format strings (Example 2) can still be used, but the output will not be as expected.

It is important to note, that the exported file is based on the actual RadGrid cells values. When DataFormatString is applied, these values will already be formatted which could be prevented by setting the SuppressColumnDataFormatStrings property to true.

Example 1

<telerik:GridBoundColumn DataType="System.DateTime" DataField="DateField" DataFormatString="{0:tt dd-MM(yyyy) }" />

Example 2

<telerik:GridBoundColumn DataType="System.Double" DataField="DoubleField" DataFormatString="{0:C2}" />

Hiding Columns / Rows

Hiding rows and columns is pretty straightforward. Actually you can hide these elements in the same way you hide them in a normal server-side scenario.

RadGrid1.MasterTableView.GetColumn("Col1").Visible = false;
RadGrid1.MasterTableView.Items[1].Visible = false; //when IgnorePaging is false
RadGrid1.MasterTableView.GetColumn("Col1").Visible = False
RadGrid1.MasterTableView.Items(1).Visible = False 'when IgnorePaging is false

Additionally you could use the Exportable property that allows you to choose whether a certain column should be included in the exported file or not. By setting this property to false the related column will be excluded from the exported file.Its default value is true.

Styling Columns / Rows / Cell

In order to style the elements of the RadGrid you could use the standard ASP.NET style properties such as ItemStyle,AlternatingItemStyle, HeaderStyle and FooterStyle to provide a custom style for the items of RadGrid control.

<AlternatingItemStyle BorderColor="Red" BorderStyle="Solid" BorderWidth="1px" />
<ItemStyle ForeColor="Green" />
<HeaderStyle BackColor="Yellow" />

Another approach is to hook OnInfrastructureExporting event handler and apply the styles in code behind. Note that styling via CSS classes is not possible.

Styling Columns

xls.Column col = e.ExportStructure.Tables[0].Columns[2];
col.Style.BackColor = Color.Gray;
col.Style.ForeColor = Color.Yellow;
Dim col As xls.Column = e.ExportStructure.Tables(0).Columns(2)
col.Style.BackColor = Color.Gray
col.Style.ForeColor = Color.Yellow

Styling Rows

xls.Row row = e.ExportStructure.Tables[0].Rows[2];
row.Style.BackColor = Color.Blue;
Dim row As xls.Row = e.ExportStructure.Tables(0).Rows(2)
row.Style.BackColor = Color.Blue

Styling Cells 1

xls.Cell cell1 = e.ExportStructure.Tables[0].Cells["B2"];
cell1.Style.BackColor = Color.Yellow;
Dim cell1 As xls.Cell = e.ExportStructure.Tables(0).Cells("B2")
cell1.Style.BackColor = Color.Yellow

Styling Cells 2

xls.Cell cell2 = e.ExportStructure.Tables[0].Cells[3, 3];
cell2.Style.ForeColor = Color.Tomato;
Dim cell2 As xls.Cell = e.ExportStructure.Tables(0).Cells(3, 3)
cell2.Style.ForeColor = Color.Tomato

Default Cell Alignment

You can specify a default alignment to all cells by using DefaultCellAlignment. This property is supported since Q2 2015 and its default value is NotSet. Typical values include Left, Right and Center.

    <Excel DefaultCellAlignment="Center" />

Additionally you can change the default alignment on OnInfrastructureExporting event.

Image Support

Xlsx supports exporting of images. The images are included automatically in the exported document and you do not have to set any specific property. Keep in mind images with an absolute or relative path are supported, but binary images are not.

Auto-fit columns width

For the XLSX format only, the R1 2020 release introduces the option to set the AutoWidth setting for the exported columns. It is based on the AutoWidth settins of the RadSpreadProcessing Library explained in RadSpreadProcessing - Auto Fit Columns Width. You can check the Export to Excel online demo for a practical demonstration.

    <Excel Format="Xlsx" AutoFitColumnWidth="AutoFitAll" />

The enum type for the AutoFitColumnWidth is Telerik.Web.UI.Export.ExportAutoFitWidthMode with the following options:

  • Disabled (default) - The width of the columns is the default one or the one defined in HeaderStyle-Width property of the column
  • AutoFitExpandOnly - Does not affect columns that are wide enough to accommodate all cells in the column
  • AutoFitAll - Resizes all columns so the column width is equal to the width of the widest cell in it
  • ExpandToFitNumberValuesWidth - It resizes columns with cells that contain only number values

Generate Export Output

RadGrid provides a convenient way to extract the XLSX output as a string without actually exporting - this is done via the GenerateXlsxOutput() method. It is available for .NET version 4.0+ and in Telerik UI for ASP.NET AJAX versions R2 2019 and later.

As of R1 2021, the GenerateXlsxOutput() method has a few overloads introduced that allow you to receive the Workbook object or byte[] of the export output.

This can be used to get the content out of multiple grids simultaneously, then modify or save it. You can check the following live demos which demonstrate a practical implementation.

  1. Export Multiple Grids
  2. Export Grid to a Preformatted Template file


// alias for the using used for shorter definition of the Workbook type
using xlsx = Telerik.Windows.Documents.Spreadsheet.Model;

// various ways to use the GenerateXlsxOutput() method
byte[] outputAsByteArray =  RadGrid1.MasterTableView.GenerateXlsxOutput<byte[]>() as byte[];
xlsx.Workbook outputAsWorkbook = RadGrid1.MasterTableView.GenerateXlsxOutput<xlsx.Workbook>() as xlsx.Workbook;
string outputAsString = RadGrid1.MasterTableView.GenerateXlsxOutput<string>() as string;
string outputAsString2 = RadGrid1.MasterTableView.GenerateXlsxOutput();
' alias for the Import used for shorter definition of the Workbook type
Imports xlsx = Telerik.Windows.Documents.Spreadsheet.Model

' various ways to use the GenerateXlsxOutput() method
Dim outputAsByteArray As Byte() = TryCast(RadGrid1.MasterTableView.GenerateXlsxOutput(Of Byte())(), Byte())
Dim outputAsWorkbook As xlsx.Workbook = TryCast(RadGrid1.MasterTableView.GenerateXlsxOutput(Of xlsx.Workbook)(), xlsx.Workbook)
Dim outputAsString As String = TryCast(RadGrid1.MasterTableView.GenerateXlsxOutput(Of String)(), String)
Dim outputAsString2 As String = RadGrid1.MasterTableView.GenerateXlsxOutput()

If you are not actually exporting the Grid after calling the GenerateXlsxOutput()and the Response is not cleared, the state of the grids may change. This is especially true when the IgnorePaging and HideStructureColumns properties are enabled. To return the original state, you can set AllowPaging to true then call the Rebind() method of the Grid. Alternatively, you can try using the Response.Redirect(Request.RawUrl); approach.


  • No hierarchy support
  • No automatic row resizing
  • Custom skins whose images are set via the ImagesPath property instead of referenced in the stylesheet.
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