[#10] MemberAdminWindow: Implement MVVM

Elwig/Helpers/Utils.cs

@@ -537,6 +537,11 @@ namespace Elwig.Helpers {
             }
         }
 
+        public static int GetEntityIdetifierForPk(params object?[] primaryKey) {
+            var pk = primaryKey.Select(k => k?.GetHashCode() ?? 0).ToArray();
+            return ((IStructuralEquatable)pk).GetHashCode(EqualityComparer<int>.Default);
+        }
+
         public static int? GetEntityIdentifier(object? obj) {
             if (obj == null) {
                 return null;