The ornamental design for a wineglassholder, as shown and described.
FIG. 1 is a top perspective view of a wine glass holder, showing my design.
FIG. 2 is a bottom perspective view thereof.
FIG. 3 is a front elevation view thereof.
FIG. 4 is a rear elevation view thereof.
FIG. 5 is a left side elevation thereof.
FIG. 6 is a right side elevation thereof.
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The broken lines shown in the drawings are included for the purpose of illustrating portions of the wine glass holder that form no part of the claimed design.