The ornamental design for a displaycase, as shown and described.
FIG. 1 is a top perspective view of a display case showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a back view thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is left side elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines of FIG. 1 illustrate a shot glass and is included for the purposes of illustrating the environment of the design only and forms no part of the claimed design.