Display Excel Spreadsheet in WinForms, C#

There're commercial WinForms libraries from DevExpress, Syncfusion and Infragistics. I'm using DevExpress. I'd suggest their WinForms Spreadsheet control inspired by Excel. They also have Spreadsheet File API for .NET and Spreadsheet UI controls for ASP.NET, MVC, WPF, ASP.NET Core and Bootstrap.

You can try their free 30-day trial and see if DevExpress UI controls suit your needs.