Me.C1TrueDBGrid1.ExportToRTF("c:\temp\composers.rtf")

this.c1TrueDBGrid1.ExportToRTF(@"c:\temp\composers.rtf");

Note: TrueDBGrid's export and printing features uses the C1.Win.Printing NuGet package, which provides three libraries: C1.PrintDocument, C1.Win.PrintPreview and C1.Win.RibbonPreview. Each library provides a set of previewing controls or components. The PrintDocument library provides the PrintDocument and MultiDocument components, the PrintPreview library provides the PreviewOutlineView, PreviewPane, PreviewTextSearchPanel, Thumbnail, PrintPreviewControl and PrintPreviewDialog components, and RibbonPreview  provides the RibbonPreview and RibbonPreviewDialog components. Since C1Report is now obsolete, make sure that the references for C1Report libraries is replaced by  individual library references in the C1.Win.Printing nuget.