Indicates whether to use the thumbnails grid.
true to use the thumbnails grid; otherwise, false. Default value is true.
When the value of UseGrids is true, then this class loads the thumbnail of the pages using a grid (through the use of DocumentImages.GetThumbnailsGrid and DocumentViewerOperation.GetThumbnail operation will not contain the thumbnail image data in the DocumentViewerOperationEventArgs.Data1 member.
When the value of UseGrids is false (the default), then this class loads the thumbnail of the pages one at a time (through the use of DocumentPage.GetThumbnailImage and DocumentViewerOperation.GetThumbnail operation will contain the thumbnail image data in the DocumentViewerOperationEventArgs.Data1 member.
The number of thumbnails to obtain depends on the size of the grid stored in GridPixelSize. The library uses this value as well as the default thumbnail size to calculate the number of thumbnail images that fit in a single grid.
Note that if the value of UseGrids is true, then WorkerCount is not used (assumed to be 1 always).
Note that UseGrids is ignored if the document is not read-only since pages from various documents can be added in any order and the grid technique will have no advantage in this case.