Infragistics.Excel is an extremely powerful, yet little known API. It has the capability to build an entire Excel Workbook (and multiple worksheets). You can add formulas and interact with an Excel document in C# code in many different fashions. On the roadmap for Infragistics WPF is to add support for a single method call to export the XamDataGrid to Excel; in the meantime, this code library gives you the basic functionality in a single class that you can easily re-use to achieve the exporting work.
Basically, the class loops through RecordsCollection (also checks for records in the GroupByRecordsCollection) and creates a Infragistics.Excel.WorkSheetRow for each record.
To consume this class, simply new up the exporter class and call the export method:
xamDataGridExcelExporter.xamDataGridExcelExporter xamDataGridExcelExporter1 =
You can find the sample code here.