Not certain but would put money on this Alexander Dandridge being the grandson of Nathaniel West and Dorothy Spotswood Dandridge and the son of Robert Ambler Dandridge (1760-1799) and Mildred Aylett Allen (1753-aft. 1801). R.A and Mildred Dandridge had 6 kids, one of whom was an Alexander Spotswood Dandridge (b. 6 Apr. 1786) I do not have other dates or locations on this Alexander; have several other Alexander's and none come close to your ca. 1792 date.Also have this Alexander married to Jane Lewis 24 Dec. 1807 in Goochland Co., Va.