Cogenesis IT Consulting said:

How can I cahnge the Font color in the Excel  exporting worksheet.

Use the FormattedString and FormattedStringFont objects, for an example see my blog posting,

https://ko.infragistics.com/community/blogs/b/derek_harmon/posts/coloring-keywords-in-your-excel-worksheet

My example is written in the context of a WebGrid export operation, but you can use it directly through the Infragistics.Excel class library API.  The common factor whether you're doing this as part of a WebGrid export or programmatically in the API is the WorksheetCell object you can get by indexing the rows and columns of a Worksheet.