1

Yes.Application/Admins/Categories/DeleteCategoryCommandHandler.cs

@@ -2,12 +2,38 @@
 {
     public record DeleteCategoryCommand(int Id) : IRequest<Unit>;
 
-    public class DeleteCategoryCommandHandler(BlogDbContext db) : IRequestHandler<DeleteCategoryCommand, Unit>
+    public class DeleteCategoryCommandHandler(
+        BlogDbContext db,
+        IIdentityContext identity) : IRequestHandler<DeleteCategoryCommand, Unit>
     {
         private readonly BlogDbContext _db = db;
+        private readonly IIdentityContext _identity = identity;
 
         public async Task<Unit> Handle(DeleteCategoryCommand request, CancellationToken cancellationToken)
         {
+            var identityUser = await _db.Users.FindAsync(_identity.Id);
+            if (identityUser == null)
+            {
+                throw new UserNotExistsException(_identity.Id);
+            }
+
+            if (!identityUser.IsSystemUser())
+            {
+                throw new AccessDeniedException();
+            }
+
+            var hasArticlesInCategory = await _db.Articles.AnyAsync(x => x.CategoryId == request.Id, cancellationToken);
+            if (hasArticlesInCategory)
+            {
+                throw new DeleteCategoryException("分类下还有文章，无法删除！");
+            }
+
+            var categoryCount = await _db.Categories.CountAsync(cancellationToken);
+            if (categoryCount <= 1)
+            {
+                throw new DeleteCategoryException("至少要保留一个分类！");
+            }
+
             var category = await _db.Categories.FindAsync(request.Id);
             if (category != null)
             {