No, this information is not available as a public property. We thought about adding such a property in iGrid.NET X, but it turned out that the number of visible rows varies for the same grid in different contexts and one property is not enough or it can be misinterpreted. You can wonder why - that's why.
In the simplest case, when iGrid contains only normal rows (no group rows), and if it is not a tree grid, the number of visible rows is almost obvious - it's the number of rows with the Visible status set to True. Right? Not fully. What about rows with 0 height? Add to this the situation of a grouped grid. Should we take into account group rows when we count visible rows? What if we collapse some group rows - should we count collapsed normal rows as visible? The same for a tree grid.
Most likely, we need a bunch of properties returning all possible row count metrics. What do you think?
P.S. Moving this discussion in the more appropriate Suggestions section. Perhaps, if this question becomes more clear, we'll implement a property or properties for row counts in the future updates.